1 /*-------------------------------------------------------------------------
2 *
3 * parse_clause.c
4 * handle clauses in parser
5 *
6 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/parser/parse_clause.c
12 *
13 *-------------------------------------------------------------------------
14 */
15
16 #include "postgres.h"
17
18 #include "access/htup_details.h"
19 #include "access/nbtree.h"
20 #include "access/table.h"
21 #include "access/tsmapi.h"
22 #include "catalog/catalog.h"
23 #include "catalog/heap.h"
24 #include "catalog/pg_am.h"
25 #include "catalog/pg_amproc.h"
26 #include "catalog/pg_collation.h"
27 #include "catalog/pg_constraint.h"
28 #include "catalog/pg_type.h"
29 #include "commands/defrem.h"
30 #include "miscadmin.h"
31 #include "nodes/makefuncs.h"
32 #include "nodes/nodeFuncs.h"
33 #include "optimizer/optimizer.h"
34 #include "parser/analyze.h"
35 #include "parser/parse_clause.h"
36 #include "parser/parse_coerce.h"
37 #include "parser/parse_collate.h"
38 #include "parser/parse_expr.h"
39 #include "parser/parse_func.h"
40 #include "parser/parse_oper.h"
41 #include "parser/parse_relation.h"
42 #include "parser/parse_target.h"
43 #include "parser/parse_type.h"
44 #include "parser/parser.h"
45 #include "parser/parsetree.h"
46 #include "rewrite/rewriteManip.h"
47 #include "utils/builtins.h"
48 #include "utils/catcache.h"
49 #include "utils/guc.h"
50 #include "utils/lsyscache.h"
51 #include "utils/rel.h"
52 #include "utils/syscache.h"
53
54
55 static int extractRemainingColumns(ParseNamespaceColumn *src_nscolumns,
56 List *src_colnames,
57 List **src_colnos,
58 List **res_colnames, List **res_colvars,
59 ParseNamespaceColumn *res_nscolumns);
60 static Node *transformJoinUsingClause(ParseState *pstate,
61 List *leftVars, List *rightVars);
62 static Node *transformJoinOnClause(ParseState *pstate, JoinExpr *j,
63 List *namespace);
64 static ParseNamespaceItem *transformTableEntry(ParseState *pstate, RangeVar *r);
65 static ParseNamespaceItem *transformRangeSubselect(ParseState *pstate,
66 RangeSubselect *r);
67 static ParseNamespaceItem *transformRangeFunction(ParseState *pstate,
68 RangeFunction *r);
69 static ParseNamespaceItem *transformRangeTableFunc(ParseState *pstate,
70 RangeTableFunc *t);
71 static TableSampleClause *transformRangeTableSample(ParseState *pstate,
72 RangeTableSample *rts);
73 static ParseNamespaceItem *getNSItemForSpecialRelationTypes(ParseState *pstate,
74 RangeVar *rv);
75 static Node *transformFromClauseItem(ParseState *pstate, Node *n,
76 ParseNamespaceItem **top_nsitem,
77 List **namespace);
78 static Var *buildVarFromNSColumn(ParseNamespaceColumn *nscol);
79 static Node *buildMergedJoinVar(ParseState *pstate, JoinType jointype,
80 Var *l_colvar, Var *r_colvar);
81 static void setNamespaceColumnVisibility(List *namespace, bool cols_visible);
82 static void setNamespaceLateralState(List *namespace,
83 bool lateral_only, bool lateral_ok);
84 static void checkExprIsVarFree(ParseState *pstate, Node *n,
85 const char *constructName);
86 static TargetEntry *findTargetlistEntrySQL92(ParseState *pstate, Node *node,
87 List **tlist, ParseExprKind exprKind);
88 static TargetEntry *findTargetlistEntrySQL99(ParseState *pstate, Node *node,
89 List **tlist, ParseExprKind exprKind);
90 static int get_matching_location(int sortgroupref,
91 List *sortgrouprefs, List *exprs);
92 static List *resolve_unique_index_expr(ParseState *pstate, InferClause *infer,
93 Relation heapRel);
94 static List *addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
95 List *grouplist, List *targetlist, int location);
96 static WindowClause *findWindowClause(List *wclist, const char *name);
97 static Node *transformFrameOffset(ParseState *pstate, int frameOptions,
98 Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc,
99 Node *clause);
100
101
102 /*
103 * transformFromClause -
104 * Process the FROM clause and add items to the query's range table,
105 * joinlist, and namespace.
106 *
107 * Note: we assume that the pstate's p_rtable, p_joinlist, and p_namespace
108 * lists were initialized to NIL when the pstate was created.
109 * We will add onto any entries already present --- this is needed for rule
110 * processing, as well as for UPDATE and DELETE.
111 */
112 void
transformFromClause(ParseState * pstate,List * frmList)113 transformFromClause(ParseState *pstate, List *frmList)
114 {
115 ListCell *fl;
116
117 /*
118 * The grammar will have produced a list of RangeVars, RangeSubselects,
119 * RangeFunctions, and/or JoinExprs. Transform each one (possibly adding
120 * entries to the rtable), check for duplicate refnames, and then add it
121 * to the joinlist and namespace.
122 *
123 * Note we must process the items left-to-right for proper handling of
124 * LATERAL references.
125 */
126 foreach(fl, frmList)
127 {
128 Node *n = lfirst(fl);
129 ParseNamespaceItem *nsitem;
130 List *namespace;
131
132 n = transformFromClauseItem(pstate, n,
133 &nsitem,
134 &namespace);
135
136 checkNameSpaceConflicts(pstate, pstate->p_namespace, namespace);
137
138 /* Mark the new namespace items as visible only to LATERAL */
139 setNamespaceLateralState(namespace, true, true);
140
141 pstate->p_joinlist = lappend(pstate->p_joinlist, n);
142 pstate->p_namespace = list_concat(pstate->p_namespace, namespace);
143 }
144
145 /*
146 * We're done parsing the FROM list, so make all namespace items
147 * unconditionally visible. Note that this will also reset lateral_only
148 * for any namespace items that were already present when we were called;
149 * but those should have been that way already.
150 */
151 setNamespaceLateralState(pstate->p_namespace, false, true);
152 }
153
154 /*
155 * setTargetTable
156 * Add the target relation of INSERT/UPDATE/DELETE to the range table,
157 * and make the special links to it in the ParseState.
158 *
159 * We also open the target relation and acquire a write lock on it.
160 * This must be done before processing the FROM list, in case the target
161 * is also mentioned as a source relation --- we want to be sure to grab
162 * the write lock before any read lock.
163 *
164 * If alsoSource is true, add the target to the query's joinlist and
165 * namespace. For INSERT, we don't want the target to be joined to;
166 * it's a destination of tuples, not a source. For UPDATE/DELETE,
167 * we do need to scan or join the target. (NOTE: we do not bother
168 * to check for namespace conflict; we assume that the namespace was
169 * initially empty in these cases.)
170 *
171 * Finally, we mark the relation as requiring the permissions specified
172 * by requiredPerms.
173 *
174 * Returns the rangetable index of the target relation.
175 */
176 int
setTargetTable(ParseState * pstate,RangeVar * relation,bool inh,bool alsoSource,AclMode requiredPerms)177 setTargetTable(ParseState *pstate, RangeVar *relation,
178 bool inh, bool alsoSource, AclMode requiredPerms)
179 {
180 ParseNamespaceItem *nsitem;
181
182 /*
183 * ENRs hide tables of the same name, so we need to check for them first.
184 * In contrast, CTEs don't hide tables (for this purpose).
185 */
186 if (relation->schemaname == NULL &&
187 scanNameSpaceForENR(pstate, relation->relname))
188 ereport(ERROR,
189 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
190 errmsg("relation \"%s\" cannot be the target of a modifying statement",
191 relation->relname)));
192
193 /* Close old target; this could only happen for multi-action rules */
194 if (pstate->p_target_relation != NULL)
195 table_close(pstate->p_target_relation, NoLock);
196
197 /*
198 * Open target rel and grab suitable lock (which we will hold till end of
199 * transaction).
200 *
201 * free_parsestate() will eventually do the corresponding table_close(),
202 * but *not* release the lock.
203 */
204 pstate->p_target_relation = parserOpenTable(pstate, relation,
205 RowExclusiveLock);
206
207 /*
208 * Now build an RTE and a ParseNamespaceItem.
209 */
210 nsitem = addRangeTableEntryForRelation(pstate, pstate->p_target_relation,
211 RowExclusiveLock,
212 relation->alias, inh, false);
213
214 /* remember the RTE/nsitem as being the query target */
215 pstate->p_target_nsitem = nsitem;
216
217 /*
218 * Override addRangeTableEntry's default ACL_SELECT permissions check, and
219 * instead mark target table as requiring exactly the specified
220 * permissions.
221 *
222 * If we find an explicit reference to the rel later during parse
223 * analysis, we will add the ACL_SELECT bit back again; see
224 * markVarForSelectPriv and its callers.
225 */
226 nsitem->p_rte->requiredPerms = requiredPerms;
227
228 /*
229 * If UPDATE/DELETE, add table to joinlist and namespace.
230 */
231 if (alsoSource)
232 addNSItemToQuery(pstate, nsitem, true, true, true);
233
234 return nsitem->p_rtindex;
235 }
236
237 /*
238 * Extract all not-in-common columns from column lists of a source table
239 *
240 * src_nscolumns and src_colnames describe the source table.
241 *
242 * *src_colnos initially contains the column numbers of the already-merged
243 * columns. We add to it the column number of each additional column.
244 * Also append to *res_colnames the name of each additional column,
245 * append to *res_colvars a Var for each additional column, and copy the
246 * columns' nscolumns data into res_nscolumns[] (which is caller-allocated
247 * space that had better be big enough).
248 *
249 * Returns the number of columns added.
250 */
251 static int
extractRemainingColumns(ParseNamespaceColumn * src_nscolumns,List * src_colnames,List ** src_colnos,List ** res_colnames,List ** res_colvars,ParseNamespaceColumn * res_nscolumns)252 extractRemainingColumns(ParseNamespaceColumn *src_nscolumns,
253 List *src_colnames,
254 List **src_colnos,
255 List **res_colnames, List **res_colvars,
256 ParseNamespaceColumn *res_nscolumns)
257 {
258 int colcount = 0;
259 Bitmapset *prevcols;
260 int attnum;
261 ListCell *lc;
262
263 /*
264 * While we could just test "list_member_int(*src_colnos, attnum)" to
265 * detect already-merged columns in the loop below, that would be O(N^2)
266 * for a wide input table. Instead build a bitmapset of just the merged
267 * USING columns, which we won't add to within the main loop.
268 */
269 prevcols = NULL;
270 foreach(lc, *src_colnos)
271 {
272 prevcols = bms_add_member(prevcols, lfirst_int(lc));
273 }
274
275 attnum = 0;
276 foreach(lc, src_colnames)
277 {
278 char *colname = strVal(lfirst(lc));
279
280 attnum++;
281 /* Non-dropped and not already merged? */
282 if (colname[0] != '\0' && !bms_is_member(attnum, prevcols))
283 {
284 /* Yes, so emit it as next output column */
285 *src_colnos = lappend_int(*src_colnos, attnum);
286 *res_colnames = lappend(*res_colnames, lfirst(lc));
287 *res_colvars = lappend(*res_colvars,
288 buildVarFromNSColumn(src_nscolumns + attnum - 1));
289 /* Copy the input relation's nscolumn data for this column */
290 res_nscolumns[colcount] = src_nscolumns[attnum - 1];
291 colcount++;
292 }
293 }
294 return colcount;
295 }
296
297 /* transformJoinUsingClause()
298 * Build a complete ON clause from a partially-transformed USING list.
299 * We are given lists of nodes representing left and right match columns.
300 * Result is a transformed qualification expression.
301 */
302 static Node *
transformJoinUsingClause(ParseState * pstate,List * leftVars,List * rightVars)303 transformJoinUsingClause(ParseState *pstate,
304 List *leftVars, List *rightVars)
305 {
306 Node *result;
307 List *andargs = NIL;
308 ListCell *lvars,
309 *rvars;
310
311 /*
312 * We cheat a little bit here by building an untransformed operator tree
313 * whose leaves are the already-transformed Vars. This requires collusion
314 * from transformExpr(), which normally could be expected to complain
315 * about already-transformed subnodes. However, this does mean that we
316 * have to mark the columns as requiring SELECT privilege for ourselves;
317 * transformExpr() won't do it.
318 */
319 forboth(lvars, leftVars, rvars, rightVars)
320 {
321 Var *lvar = (Var *) lfirst(lvars);
322 Var *rvar = (Var *) lfirst(rvars);
323 A_Expr *e;
324
325 /* Require read access to the join variables */
326 markVarForSelectPriv(pstate, lvar);
327 markVarForSelectPriv(pstate, rvar);
328
329 /* Now create the lvar = rvar join condition */
330 e = makeSimpleA_Expr(AEXPR_OP, "=",
331 (Node *) copyObject(lvar), (Node *) copyObject(rvar),
332 -1);
333
334 /* Prepare to combine into an AND clause, if multiple join columns */
335 andargs = lappend(andargs, e);
336 }
337
338 /* Only need an AND if there's more than one join column */
339 if (list_length(andargs) == 1)
340 result = (Node *) linitial(andargs);
341 else
342 result = (Node *) makeBoolExpr(AND_EXPR, andargs, -1);
343
344 /*
345 * Since the references are already Vars, and are certainly from the input
346 * relations, we don't have to go through the same pushups that
347 * transformJoinOnClause() does. Just invoke transformExpr() to fix up
348 * the operators, and we're done.
349 */
350 result = transformExpr(pstate, result, EXPR_KIND_JOIN_USING);
351
352 result = coerce_to_boolean(pstate, result, "JOIN/USING");
353
354 return result;
355 }
356
357 /* transformJoinOnClause()
358 * Transform the qual conditions for JOIN/ON.
359 * Result is a transformed qualification expression.
360 */
361 static Node *
transformJoinOnClause(ParseState * pstate,JoinExpr * j,List * namespace)362 transformJoinOnClause(ParseState *pstate, JoinExpr *j, List *namespace)
363 {
364 Node *result;
365 List *save_namespace;
366
367 /*
368 * The namespace that the join expression should see is just the two
369 * subtrees of the JOIN plus any outer references from upper pstate
370 * levels. Temporarily set this pstate's namespace accordingly. (We need
371 * not check for refname conflicts, because transformFromClauseItem()
372 * already did.) All namespace items are marked visible regardless of
373 * LATERAL state.
374 */
375 setNamespaceLateralState(namespace, false, true);
376
377 save_namespace = pstate->p_namespace;
378 pstate->p_namespace = namespace;
379
380 result = transformWhereClause(pstate, j->quals,
381 EXPR_KIND_JOIN_ON, "JOIN/ON");
382
383 pstate->p_namespace = save_namespace;
384
385 return result;
386 }
387
388 /*
389 * transformTableEntry --- transform a RangeVar (simple relation reference)
390 */
391 static ParseNamespaceItem *
transformTableEntry(ParseState * pstate,RangeVar * r)392 transformTableEntry(ParseState *pstate, RangeVar *r)
393 {
394 /* addRangeTableEntry does all the work */
395 return addRangeTableEntry(pstate, r, r->alias, r->inh, true);
396 }
397
398 /*
399 * transformRangeSubselect --- transform a sub-SELECT appearing in FROM
400 */
401 static ParseNamespaceItem *
transformRangeSubselect(ParseState * pstate,RangeSubselect * r)402 transformRangeSubselect(ParseState *pstate, RangeSubselect *r)
403 {
404 Query *query;
405
406 /*
407 * We require user to supply an alias for a subselect, per SQL92. To relax
408 * this, we'd have to be prepared to gin up a unique alias for an
409 * unlabeled subselect. (This is just elog, not ereport, because the
410 * grammar should have enforced it already. It'd probably be better to
411 * report the error here, but we don't have a good error location here.)
412 */
413 if (r->alias == NULL)
414 elog(ERROR, "subquery in FROM must have an alias");
415
416 /*
417 * Set p_expr_kind to show this parse level is recursing to a subselect.
418 * We can't be nested within any expression, so don't need save-restore
419 * logic here.
420 */
421 Assert(pstate->p_expr_kind == EXPR_KIND_NONE);
422 pstate->p_expr_kind = EXPR_KIND_FROM_SUBSELECT;
423
424 /*
425 * If the subselect is LATERAL, make lateral_only names of this level
426 * visible to it. (LATERAL can't nest within a single pstate level, so we
427 * don't need save/restore logic here.)
428 */
429 Assert(!pstate->p_lateral_active);
430 pstate->p_lateral_active = r->lateral;
431
432 /*
433 * Analyze and transform the subquery.
434 */
435 query = parse_sub_analyze(r->subquery, pstate, NULL,
436 isLockedRefname(pstate, r->alias->aliasname),
437 true);
438
439 /* Restore state */
440 pstate->p_lateral_active = false;
441 pstate->p_expr_kind = EXPR_KIND_NONE;
442
443 /*
444 * Check that we got a SELECT. Anything else should be impossible given
445 * restrictions of the grammar, but check anyway.
446 */
447 if (!IsA(query, Query) ||
448 query->commandType != CMD_SELECT)
449 elog(ERROR, "unexpected non-SELECT command in subquery in FROM");
450
451 /*
452 * OK, build an RTE and nsitem for the subquery.
453 */
454 return addRangeTableEntryForSubquery(pstate,
455 query,
456 r->alias,
457 r->lateral,
458 true);
459 }
460
461
462 /*
463 * transformRangeFunction --- transform a function call appearing in FROM
464 */
465 static ParseNamespaceItem *
transformRangeFunction(ParseState * pstate,RangeFunction * r)466 transformRangeFunction(ParseState *pstate, RangeFunction *r)
467 {
468 List *funcexprs = NIL;
469 List *funcnames = NIL;
470 List *coldeflists = NIL;
471 bool is_lateral;
472 ListCell *lc;
473
474 /*
475 * We make lateral_only names of this level visible, whether or not the
476 * RangeFunction is explicitly marked LATERAL. This is needed for SQL
477 * spec compliance in the case of UNNEST(), and seems useful on
478 * convenience grounds for all functions in FROM.
479 *
480 * (LATERAL can't nest within a single pstate level, so we don't need
481 * save/restore logic here.)
482 */
483 Assert(!pstate->p_lateral_active);
484 pstate->p_lateral_active = true;
485
486 /*
487 * Transform the raw expressions.
488 *
489 * While transforming, also save function names for possible use as alias
490 * and column names. We use the same transformation rules as for a SELECT
491 * output expression. For a FuncCall node, the result will be the
492 * function name, but it is possible for the grammar to hand back other
493 * node types.
494 *
495 * We have to get this info now, because FigureColname only works on raw
496 * parsetrees. Actually deciding what to do with the names is left up to
497 * addRangeTableEntryForFunction.
498 *
499 * Likewise, collect column definition lists if there were any. But
500 * complain if we find one here and the RangeFunction has one too.
501 */
502 foreach(lc, r->functions)
503 {
504 List *pair = (List *) lfirst(lc);
505 Node *fexpr;
506 List *coldeflist;
507 Node *newfexpr;
508 Node *last_srf;
509
510 /* Disassemble the function-call/column-def-list pairs */
511 Assert(list_length(pair) == 2);
512 fexpr = (Node *) linitial(pair);
513 coldeflist = (List *) lsecond(pair);
514
515 /*
516 * If we find a function call unnest() with more than one argument and
517 * no special decoration, transform it into separate unnest() calls on
518 * each argument. This is a kluge, for sure, but it's less nasty than
519 * other ways of implementing the SQL-standard UNNEST() syntax.
520 *
521 * If there is any decoration (including a coldeflist), we don't
522 * transform, which probably means a no-such-function error later. We
523 * could alternatively throw an error right now, but that doesn't seem
524 * tremendously helpful. If someone is using any such decoration,
525 * then they're not using the SQL-standard syntax, and they're more
526 * likely expecting an un-tweaked function call.
527 *
528 * Note: the transformation changes a non-schema-qualified unnest()
529 * function name into schema-qualified pg_catalog.unnest(). This
530 * choice is also a bit debatable, but it seems reasonable to force
531 * use of built-in unnest() when we make this transformation.
532 */
533 if (IsA(fexpr, FuncCall))
534 {
535 FuncCall *fc = (FuncCall *) fexpr;
536
537 if (list_length(fc->funcname) == 1 &&
538 strcmp(strVal(linitial(fc->funcname)), "unnest") == 0 &&
539 list_length(fc->args) > 1 &&
540 fc->agg_order == NIL &&
541 fc->agg_filter == NULL &&
542 fc->over == NULL &&
543 !fc->agg_star &&
544 !fc->agg_distinct &&
545 !fc->func_variadic &&
546 coldeflist == NIL)
547 {
548 ListCell *lc;
549
550 foreach(lc, fc->args)
551 {
552 Node *arg = (Node *) lfirst(lc);
553 FuncCall *newfc;
554
555 last_srf = pstate->p_last_srf;
556
557 newfc = makeFuncCall(SystemFuncName("unnest"),
558 list_make1(arg),
559 COERCE_EXPLICIT_CALL,
560 fc->location);
561
562 newfexpr = transformExpr(pstate, (Node *) newfc,
563 EXPR_KIND_FROM_FUNCTION);
564
565 /* nodeFunctionscan.c requires SRFs to be at top level */
566 if (pstate->p_last_srf != last_srf &&
567 pstate->p_last_srf != newfexpr)
568 ereport(ERROR,
569 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
570 errmsg("set-returning functions must appear at top level of FROM"),
571 parser_errposition(pstate,
572 exprLocation(pstate->p_last_srf))));
573
574 funcexprs = lappend(funcexprs, newfexpr);
575
576 funcnames = lappend(funcnames,
577 FigureColname((Node *) newfc));
578
579 /* coldeflist is empty, so no error is possible */
580
581 coldeflists = lappend(coldeflists, coldeflist);
582 }
583 continue; /* done with this function item */
584 }
585 }
586
587 /* normal case ... */
588 last_srf = pstate->p_last_srf;
589
590 newfexpr = transformExpr(pstate, fexpr,
591 EXPR_KIND_FROM_FUNCTION);
592
593 /* nodeFunctionscan.c requires SRFs to be at top level */
594 if (pstate->p_last_srf != last_srf &&
595 pstate->p_last_srf != newfexpr)
596 ereport(ERROR,
597 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
598 errmsg("set-returning functions must appear at top level of FROM"),
599 parser_errposition(pstate,
600 exprLocation(pstate->p_last_srf))));
601
602 funcexprs = lappend(funcexprs, newfexpr);
603
604 funcnames = lappend(funcnames,
605 FigureColname(fexpr));
606
607 if (coldeflist && r->coldeflist)
608 ereport(ERROR,
609 (errcode(ERRCODE_SYNTAX_ERROR),
610 errmsg("multiple column definition lists are not allowed for the same function"),
611 parser_errposition(pstate,
612 exprLocation((Node *) r->coldeflist))));
613
614 coldeflists = lappend(coldeflists, coldeflist);
615 }
616
617 pstate->p_lateral_active = false;
618
619 /*
620 * We must assign collations now so that the RTE exposes correct collation
621 * info for Vars created from it.
622 */
623 assign_list_collations(pstate, funcexprs);
624
625 /*
626 * Install the top-level coldeflist if there was one (we already checked
627 * that there was no conflicting per-function coldeflist).
628 *
629 * We only allow this when there's a single function (even after UNNEST
630 * expansion) and no WITH ORDINALITY. The reason for the latter
631 * restriction is that it's not real clear whether the ordinality column
632 * should be in the coldeflist, and users are too likely to make mistakes
633 * in one direction or the other. Putting the coldeflist inside ROWS
634 * FROM() is much clearer in this case.
635 */
636 if (r->coldeflist)
637 {
638 if (list_length(funcexprs) != 1)
639 {
640 if (r->is_rowsfrom)
641 ereport(ERROR,
642 (errcode(ERRCODE_SYNTAX_ERROR),
643 errmsg("ROWS FROM() with multiple functions cannot have a column definition list"),
644 errhint("Put a separate column definition list for each function inside ROWS FROM()."),
645 parser_errposition(pstate,
646 exprLocation((Node *) r->coldeflist))));
647 else
648 ereport(ERROR,
649 (errcode(ERRCODE_SYNTAX_ERROR),
650 errmsg("UNNEST() with multiple arguments cannot have a column definition list"),
651 errhint("Use separate UNNEST() calls inside ROWS FROM(), and attach a column definition list to each one."),
652 parser_errposition(pstate,
653 exprLocation((Node *) r->coldeflist))));
654 }
655 if (r->ordinality)
656 ereport(ERROR,
657 (errcode(ERRCODE_SYNTAX_ERROR),
658 errmsg("WITH ORDINALITY cannot be used with a column definition list"),
659 errhint("Put the column definition list inside ROWS FROM()."),
660 parser_errposition(pstate,
661 exprLocation((Node *) r->coldeflist))));
662
663 coldeflists = list_make1(r->coldeflist);
664 }
665
666 /*
667 * Mark the RTE as LATERAL if the user said LATERAL explicitly, or if
668 * there are any lateral cross-references in it.
669 */
670 is_lateral = r->lateral || contain_vars_of_level((Node *) funcexprs, 0);
671
672 /*
673 * OK, build an RTE and nsitem for the function.
674 */
675 return addRangeTableEntryForFunction(pstate,
676 funcnames, funcexprs, coldeflists,
677 r, is_lateral, true);
678 }
679
680 /*
681 * transformRangeTableFunc -
682 * Transform a raw RangeTableFunc into TableFunc.
683 *
684 * Transform the namespace clauses, the document-generating expression, the
685 * row-generating expression, the column-generating expressions, and the
686 * default value expressions.
687 */
688 static ParseNamespaceItem *
transformRangeTableFunc(ParseState * pstate,RangeTableFunc * rtf)689 transformRangeTableFunc(ParseState *pstate, RangeTableFunc *rtf)
690 {
691 TableFunc *tf = makeNode(TableFunc);
692 const char *constructName;
693 Oid docType;
694 bool is_lateral;
695 ListCell *col;
696 char **names;
697 int colno;
698
699 /* Currently only XMLTABLE is supported */
700 constructName = "XMLTABLE";
701 docType = XMLOID;
702
703 /*
704 * We make lateral_only names of this level visible, whether or not the
705 * RangeTableFunc is explicitly marked LATERAL. This is needed for SQL
706 * spec compliance and seems useful on convenience grounds for all
707 * functions in FROM.
708 *
709 * (LATERAL can't nest within a single pstate level, so we don't need
710 * save/restore logic here.)
711 */
712 Assert(!pstate->p_lateral_active);
713 pstate->p_lateral_active = true;
714
715 /* Transform and apply typecast to the row-generating expression ... */
716 Assert(rtf->rowexpr != NULL);
717 tf->rowexpr = coerce_to_specific_type(pstate,
718 transformExpr(pstate, rtf->rowexpr, EXPR_KIND_FROM_FUNCTION),
719 TEXTOID,
720 constructName);
721 assign_expr_collations(pstate, tf->rowexpr);
722
723 /* ... and to the document itself */
724 Assert(rtf->docexpr != NULL);
725 tf->docexpr = coerce_to_specific_type(pstate,
726 transformExpr(pstate, rtf->docexpr, EXPR_KIND_FROM_FUNCTION),
727 docType,
728 constructName);
729 assign_expr_collations(pstate, tf->docexpr);
730
731 /* undef ordinality column number */
732 tf->ordinalitycol = -1;
733
734 /* Process column specs */
735 names = palloc(sizeof(char *) * list_length(rtf->columns));
736
737 colno = 0;
738 foreach(col, rtf->columns)
739 {
740 RangeTableFuncCol *rawc = (RangeTableFuncCol *) lfirst(col);
741 Oid typid;
742 int32 typmod;
743 Node *colexpr;
744 Node *coldefexpr;
745 int j;
746
747 tf->colnames = lappend(tf->colnames,
748 makeString(pstrdup(rawc->colname)));
749
750 /*
751 * Determine the type and typmod for the new column. FOR ORDINALITY
752 * columns are INTEGER per spec; the others are user-specified.
753 */
754 if (rawc->for_ordinality)
755 {
756 if (tf->ordinalitycol != -1)
757 ereport(ERROR,
758 (errcode(ERRCODE_SYNTAX_ERROR),
759 errmsg("only one FOR ORDINALITY column is allowed"),
760 parser_errposition(pstate, rawc->location)));
761
762 typid = INT4OID;
763 typmod = -1;
764 tf->ordinalitycol = colno;
765 }
766 else
767 {
768 if (rawc->typeName->setof)
769 ereport(ERROR,
770 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
771 errmsg("column \"%s\" cannot be declared SETOF",
772 rawc->colname),
773 parser_errposition(pstate, rawc->location)));
774
775 typenameTypeIdAndMod(pstate, rawc->typeName,
776 &typid, &typmod);
777 }
778
779 tf->coltypes = lappend_oid(tf->coltypes, typid);
780 tf->coltypmods = lappend_int(tf->coltypmods, typmod);
781 tf->colcollations = lappend_oid(tf->colcollations,
782 get_typcollation(typid));
783
784 /* Transform the PATH and DEFAULT expressions */
785 if (rawc->colexpr)
786 {
787 colexpr = coerce_to_specific_type(pstate,
788 transformExpr(pstate, rawc->colexpr,
789 EXPR_KIND_FROM_FUNCTION),
790 TEXTOID,
791 constructName);
792 assign_expr_collations(pstate, colexpr);
793 }
794 else
795 colexpr = NULL;
796
797 if (rawc->coldefexpr)
798 {
799 coldefexpr = coerce_to_specific_type_typmod(pstate,
800 transformExpr(pstate, rawc->coldefexpr,
801 EXPR_KIND_FROM_FUNCTION),
802 typid, typmod,
803 constructName);
804 assign_expr_collations(pstate, coldefexpr);
805 }
806 else
807 coldefexpr = NULL;
808
809 tf->colexprs = lappend(tf->colexprs, colexpr);
810 tf->coldefexprs = lappend(tf->coldefexprs, coldefexpr);
811
812 if (rawc->is_not_null)
813 tf->notnulls = bms_add_member(tf->notnulls, colno);
814
815 /* make sure column names are unique */
816 for (j = 0; j < colno; j++)
817 if (strcmp(names[j], rawc->colname) == 0)
818 ereport(ERROR,
819 (errcode(ERRCODE_SYNTAX_ERROR),
820 errmsg("column name \"%s\" is not unique",
821 rawc->colname),
822 parser_errposition(pstate, rawc->location)));
823 names[colno] = rawc->colname;
824
825 colno++;
826 }
827 pfree(names);
828
829 /* Namespaces, if any, also need to be transformed */
830 if (rtf->namespaces != NIL)
831 {
832 ListCell *ns;
833 ListCell *lc2;
834 List *ns_uris = NIL;
835 List *ns_names = NIL;
836 bool default_ns_seen = false;
837
838 foreach(ns, rtf->namespaces)
839 {
840 ResTarget *r = (ResTarget *) lfirst(ns);
841 Node *ns_uri;
842
843 Assert(IsA(r, ResTarget));
844 ns_uri = transformExpr(pstate, r->val, EXPR_KIND_FROM_FUNCTION);
845 ns_uri = coerce_to_specific_type(pstate, ns_uri,
846 TEXTOID, constructName);
847 assign_expr_collations(pstate, ns_uri);
848 ns_uris = lappend(ns_uris, ns_uri);
849
850 /* Verify consistency of name list: no dupes, only one DEFAULT */
851 if (r->name != NULL)
852 {
853 foreach(lc2, ns_names)
854 {
855 Value *ns_node = (Value *) lfirst(lc2);
856
857 if (ns_node == NULL)
858 continue;
859 if (strcmp(strVal(ns_node), r->name) == 0)
860 ereport(ERROR,
861 (errcode(ERRCODE_SYNTAX_ERROR),
862 errmsg("namespace name \"%s\" is not unique",
863 r->name),
864 parser_errposition(pstate, r->location)));
865 }
866 }
867 else
868 {
869 if (default_ns_seen)
870 ereport(ERROR,
871 (errcode(ERRCODE_SYNTAX_ERROR),
872 errmsg("only one default namespace is allowed"),
873 parser_errposition(pstate, r->location)));
874 default_ns_seen = true;
875 }
876
877 /* We represent DEFAULT by a null pointer */
878 ns_names = lappend(ns_names,
879 r->name ? makeString(r->name) : NULL);
880 }
881
882 tf->ns_uris = ns_uris;
883 tf->ns_names = ns_names;
884 }
885
886 tf->location = rtf->location;
887
888 pstate->p_lateral_active = false;
889
890 /*
891 * Mark the RTE as LATERAL if the user said LATERAL explicitly, or if
892 * there are any lateral cross-references in it.
893 */
894 is_lateral = rtf->lateral || contain_vars_of_level((Node *) tf, 0);
895
896 return addRangeTableEntryForTableFunc(pstate,
897 tf, rtf->alias, is_lateral, true);
898 }
899
900 /*
901 * transformRangeTableSample --- transform a TABLESAMPLE clause
902 *
903 * Caller has already transformed rts->relation, we just have to validate
904 * the remaining fields and create a TableSampleClause node.
905 */
906 static TableSampleClause *
transformRangeTableSample(ParseState * pstate,RangeTableSample * rts)907 transformRangeTableSample(ParseState *pstate, RangeTableSample *rts)
908 {
909 TableSampleClause *tablesample;
910 Oid handlerOid;
911 Oid funcargtypes[1];
912 TsmRoutine *tsm;
913 List *fargs;
914 ListCell *larg,
915 *ltyp;
916
917 /*
918 * To validate the sample method name, look up the handler function, which
919 * has the same name, one dummy INTERNAL argument, and a result type of
920 * tsm_handler. (Note: tablesample method names are not schema-qualified
921 * in the SQL standard; but since they are just functions to us, we allow
922 * schema qualification to resolve any potential ambiguity.)
923 */
924 funcargtypes[0] = INTERNALOID;
925
926 handlerOid = LookupFuncName(rts->method, 1, funcargtypes, true);
927
928 /* we want error to complain about no-such-method, not no-such-function */
929 if (!OidIsValid(handlerOid))
930 ereport(ERROR,
931 (errcode(ERRCODE_UNDEFINED_OBJECT),
932 errmsg("tablesample method %s does not exist",
933 NameListToString(rts->method)),
934 parser_errposition(pstate, rts->location)));
935
936 /* check that handler has correct return type */
937 if (get_func_rettype(handlerOid) != TSM_HANDLEROID)
938 ereport(ERROR,
939 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
940 errmsg("function %s must return type %s",
941 NameListToString(rts->method), "tsm_handler"),
942 parser_errposition(pstate, rts->location)));
943
944 /* OK, run the handler to get TsmRoutine, for argument type info */
945 tsm = GetTsmRoutine(handlerOid);
946
947 tablesample = makeNode(TableSampleClause);
948 tablesample->tsmhandler = handlerOid;
949
950 /* check user provided the expected number of arguments */
951 if (list_length(rts->args) != list_length(tsm->parameterTypes))
952 ereport(ERROR,
953 (errcode(ERRCODE_INVALID_TABLESAMPLE_ARGUMENT),
954 errmsg_plural("tablesample method %s requires %d argument, not %d",
955 "tablesample method %s requires %d arguments, not %d",
956 list_length(tsm->parameterTypes),
957 NameListToString(rts->method),
958 list_length(tsm->parameterTypes),
959 list_length(rts->args)),
960 parser_errposition(pstate, rts->location)));
961
962 /*
963 * Transform the arguments, typecasting them as needed. Note we must also
964 * assign collations now, because assign_query_collations() doesn't
965 * examine any substructure of RTEs.
966 */
967 fargs = NIL;
968 forboth(larg, rts->args, ltyp, tsm->parameterTypes)
969 {
970 Node *arg = (Node *) lfirst(larg);
971 Oid argtype = lfirst_oid(ltyp);
972
973 arg = transformExpr(pstate, arg, EXPR_KIND_FROM_FUNCTION);
974 arg = coerce_to_specific_type(pstate, arg, argtype, "TABLESAMPLE");
975 assign_expr_collations(pstate, arg);
976 fargs = lappend(fargs, arg);
977 }
978 tablesample->args = fargs;
979
980 /* Process REPEATABLE (seed) */
981 if (rts->repeatable != NULL)
982 {
983 Node *arg;
984
985 if (!tsm->repeatable_across_queries)
986 ereport(ERROR,
987 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
988 errmsg("tablesample method %s does not support REPEATABLE",
989 NameListToString(rts->method)),
990 parser_errposition(pstate, rts->location)));
991
992 arg = transformExpr(pstate, rts->repeatable, EXPR_KIND_FROM_FUNCTION);
993 arg = coerce_to_specific_type(pstate, arg, FLOAT8OID, "REPEATABLE");
994 assign_expr_collations(pstate, arg);
995 tablesample->repeatable = (Expr *) arg;
996 }
997 else
998 tablesample->repeatable = NULL;
999
1000 return tablesample;
1001 }
1002
1003 /*
1004 * getNSItemForSpecialRelationTypes
1005 *
1006 * If given RangeVar refers to a CTE or an EphemeralNamedRelation,
1007 * build and return an appropriate ParseNamespaceItem, otherwise return NULL
1008 */
1009 static ParseNamespaceItem *
getNSItemForSpecialRelationTypes(ParseState * pstate,RangeVar * rv)1010 getNSItemForSpecialRelationTypes(ParseState *pstate, RangeVar *rv)
1011 {
1012 ParseNamespaceItem *nsitem;
1013 CommonTableExpr *cte;
1014 Index levelsup;
1015
1016 /*
1017 * if it is a qualified name, it can't be a CTE or tuplestore reference
1018 */
1019 if (rv->schemaname)
1020 return NULL;
1021
1022 cte = scanNameSpaceForCTE(pstate, rv->relname, &levelsup);
1023 if (cte)
1024 nsitem = addRangeTableEntryForCTE(pstate, cte, levelsup, rv, true);
1025 else if (scanNameSpaceForENR(pstate, rv->relname))
1026 nsitem = addRangeTableEntryForENR(pstate, rv, true);
1027 else
1028 nsitem = NULL;
1029
1030 return nsitem;
1031 }
1032
1033 /*
1034 * transformFromClauseItem -
1035 * Transform a FROM-clause item, adding any required entries to the
1036 * range table list being built in the ParseState, and return the
1037 * transformed item ready to include in the joinlist. Also build a
1038 * ParseNamespaceItem list describing the names exposed by this item.
1039 * This routine can recurse to handle SQL92 JOIN expressions.
1040 *
1041 * The function return value is the node to add to the jointree (a
1042 * RangeTblRef or JoinExpr). Additional output parameters are:
1043 *
1044 * *top_nsitem: receives the ParseNamespaceItem directly corresponding to the
1045 * jointree item. (This is only used during internal recursion, not by
1046 * outside callers.)
1047 *
1048 * *namespace: receives a List of ParseNamespaceItems for the RTEs exposed
1049 * as table/column names by this item. (The lateral_only flags in these items
1050 * are indeterminate and should be explicitly set by the caller before use.)
1051 */
1052 static Node *
transformFromClauseItem(ParseState * pstate,Node * n,ParseNamespaceItem ** top_nsitem,List ** namespace)1053 transformFromClauseItem(ParseState *pstate, Node *n,
1054 ParseNamespaceItem **top_nsitem,
1055 List **namespace)
1056 {
1057 if (IsA(n, RangeVar))
1058 {
1059 /* Plain relation reference, or perhaps a CTE reference */
1060 RangeVar *rv = (RangeVar *) n;
1061 RangeTblRef *rtr;
1062 ParseNamespaceItem *nsitem;
1063
1064 /* Check if it's a CTE or tuplestore reference */
1065 nsitem = getNSItemForSpecialRelationTypes(pstate, rv);
1066
1067 /* if not found above, must be a table reference */
1068 if (!nsitem)
1069 nsitem = transformTableEntry(pstate, rv);
1070
1071 *top_nsitem = nsitem;
1072 *namespace = list_make1(nsitem);
1073 rtr = makeNode(RangeTblRef);
1074 rtr->rtindex = nsitem->p_rtindex;
1075 return (Node *) rtr;
1076 }
1077 else if (IsA(n, RangeSubselect))
1078 {
1079 /* sub-SELECT is like a plain relation */
1080 RangeTblRef *rtr;
1081 ParseNamespaceItem *nsitem;
1082
1083 nsitem = transformRangeSubselect(pstate, (RangeSubselect *) n);
1084 *top_nsitem = nsitem;
1085 *namespace = list_make1(nsitem);
1086 rtr = makeNode(RangeTblRef);
1087 rtr->rtindex = nsitem->p_rtindex;
1088 return (Node *) rtr;
1089 }
1090 else if (IsA(n, RangeFunction))
1091 {
1092 /* function is like a plain relation */
1093 RangeTblRef *rtr;
1094 ParseNamespaceItem *nsitem;
1095
1096 nsitem = transformRangeFunction(pstate, (RangeFunction *) n);
1097 *top_nsitem = nsitem;
1098 *namespace = list_make1(nsitem);
1099 rtr = makeNode(RangeTblRef);
1100 rtr->rtindex = nsitem->p_rtindex;
1101 return (Node *) rtr;
1102 }
1103 else if (IsA(n, RangeTableFunc))
1104 {
1105 /* table function is like a plain relation */
1106 RangeTblRef *rtr;
1107 ParseNamespaceItem *nsitem;
1108
1109 nsitem = transformRangeTableFunc(pstate, (RangeTableFunc *) n);
1110 *top_nsitem = nsitem;
1111 *namespace = list_make1(nsitem);
1112 rtr = makeNode(RangeTblRef);
1113 rtr->rtindex = nsitem->p_rtindex;
1114 return (Node *) rtr;
1115 }
1116 else if (IsA(n, RangeTableSample))
1117 {
1118 /* TABLESAMPLE clause (wrapping some other valid FROM node) */
1119 RangeTableSample *rts = (RangeTableSample *) n;
1120 Node *rel;
1121 RangeTblEntry *rte;
1122
1123 /* Recursively transform the contained relation */
1124 rel = transformFromClauseItem(pstate, rts->relation,
1125 top_nsitem, namespace);
1126 rte = (*top_nsitem)->p_rte;
1127 /* We only support this on plain relations and matviews */
1128 if (rte->rtekind != RTE_RELATION ||
1129 (rte->relkind != RELKIND_RELATION &&
1130 rte->relkind != RELKIND_MATVIEW &&
1131 rte->relkind != RELKIND_PARTITIONED_TABLE))
1132 ereport(ERROR,
1133 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1134 errmsg("TABLESAMPLE clause can only be applied to tables and materialized views"),
1135 parser_errposition(pstate, exprLocation(rts->relation))));
1136
1137 /* Transform TABLESAMPLE details and attach to the RTE */
1138 rte->tablesample = transformRangeTableSample(pstate, rts);
1139 return rel;
1140 }
1141 else if (IsA(n, JoinExpr))
1142 {
1143 /* A newfangled join expression */
1144 JoinExpr *j = (JoinExpr *) n;
1145 ParseNamespaceItem *nsitem;
1146 ParseNamespaceItem *l_nsitem;
1147 ParseNamespaceItem *r_nsitem;
1148 List *l_namespace,
1149 *r_namespace,
1150 *my_namespace,
1151 *l_colnames,
1152 *r_colnames,
1153 *res_colnames,
1154 *l_colnos,
1155 *r_colnos,
1156 *res_colvars;
1157 ParseNamespaceColumn *l_nscolumns,
1158 *r_nscolumns,
1159 *res_nscolumns;
1160 int res_colindex;
1161 bool lateral_ok;
1162 int sv_namespace_length;
1163 int k;
1164
1165 /*
1166 * Recursively process the left subtree, then the right. We must do
1167 * it in this order for correct visibility of LATERAL references.
1168 */
1169 j->larg = transformFromClauseItem(pstate, j->larg,
1170 &l_nsitem,
1171 &l_namespace);
1172
1173 /*
1174 * Make the left-side RTEs available for LATERAL access within the
1175 * right side, by temporarily adding them to the pstate's namespace
1176 * list. Per SQL:2008, if the join type is not INNER or LEFT then the
1177 * left-side names must still be exposed, but it's an error to
1178 * reference them. (Stupid design, but that's what it says.) Hence,
1179 * we always push them into the namespace, but mark them as not
1180 * lateral_ok if the jointype is wrong.
1181 *
1182 * Notice that we don't require the merged namespace list to be
1183 * conflict-free. See the comments for scanNameSpaceForRefname().
1184 */
1185 lateral_ok = (j->jointype == JOIN_INNER || j->jointype == JOIN_LEFT);
1186 setNamespaceLateralState(l_namespace, true, lateral_ok);
1187
1188 sv_namespace_length = list_length(pstate->p_namespace);
1189 pstate->p_namespace = list_concat(pstate->p_namespace, l_namespace);
1190
1191 /* And now we can process the RHS */
1192 j->rarg = transformFromClauseItem(pstate, j->rarg,
1193 &r_nsitem,
1194 &r_namespace);
1195
1196 /* Remove the left-side RTEs from the namespace list again */
1197 pstate->p_namespace = list_truncate(pstate->p_namespace,
1198 sv_namespace_length);
1199
1200 /*
1201 * Check for conflicting refnames in left and right subtrees. Must do
1202 * this because higher levels will assume I hand back a self-
1203 * consistent namespace list.
1204 */
1205 checkNameSpaceConflicts(pstate, l_namespace, r_namespace);
1206
1207 /*
1208 * Generate combined namespace info for possible use below.
1209 */
1210 my_namespace = list_concat(l_namespace, r_namespace);
1211
1212 /*
1213 * We'll work from the nscolumns data and eref alias column names for
1214 * each of the input nsitems. Note that these include dropped
1215 * columns, which is helpful because we can keep track of physical
1216 * input column numbers more easily.
1217 */
1218 l_nscolumns = l_nsitem->p_nscolumns;
1219 l_colnames = l_nsitem->p_names->colnames;
1220 r_nscolumns = r_nsitem->p_nscolumns;
1221 r_colnames = r_nsitem->p_names->colnames;
1222
1223 /*
1224 * Natural join does not explicitly specify columns; must generate
1225 * columns to join. Need to run through the list of columns from each
1226 * table or join result and match up the column names. Use the first
1227 * table, and check every column in the second table for a match.
1228 * (We'll check that the matches were unique later on.) The result of
1229 * this step is a list of column names just like an explicitly-written
1230 * USING list.
1231 */
1232 if (j->isNatural)
1233 {
1234 List *rlist = NIL;
1235 ListCell *lx,
1236 *rx;
1237
1238 Assert(j->usingClause == NIL); /* shouldn't have USING() too */
1239
1240 foreach(lx, l_colnames)
1241 {
1242 char *l_colname = strVal(lfirst(lx));
1243 Value *m_name = NULL;
1244
1245 if (l_colname[0] == '\0')
1246 continue; /* ignore dropped columns */
1247
1248 foreach(rx, r_colnames)
1249 {
1250 char *r_colname = strVal(lfirst(rx));
1251
1252 if (strcmp(l_colname, r_colname) == 0)
1253 {
1254 m_name = makeString(l_colname);
1255 break;
1256 }
1257 }
1258
1259 /* matched a right column? then keep as join column... */
1260 if (m_name != NULL)
1261 rlist = lappend(rlist, m_name);
1262 }
1263
1264 j->usingClause = rlist;
1265 }
1266
1267 /*
1268 * If a USING clause alias was specified, save the USING columns as
1269 * its column list.
1270 */
1271 if (j->join_using_alias)
1272 j->join_using_alias->colnames = j->usingClause;
1273
1274 /*
1275 * Now transform the join qualifications, if any.
1276 */
1277 l_colnos = NIL;
1278 r_colnos = NIL;
1279 res_colnames = NIL;
1280 res_colvars = NIL;
1281
1282 /* this may be larger than needed, but it's not worth being exact */
1283 res_nscolumns = (ParseNamespaceColumn *)
1284 palloc0((list_length(l_colnames) + list_length(r_colnames)) *
1285 sizeof(ParseNamespaceColumn));
1286 res_colindex = 0;
1287
1288 if (j->usingClause)
1289 {
1290 /*
1291 * JOIN/USING (or NATURAL JOIN, as transformed above). Transform
1292 * the list into an explicit ON-condition, and generate a list of
1293 * merged result columns.
1294 */
1295 List *ucols = j->usingClause;
1296 List *l_usingvars = NIL;
1297 List *r_usingvars = NIL;
1298 ListCell *ucol;
1299
1300 Assert(j->quals == NULL); /* shouldn't have ON() too */
1301
1302 foreach(ucol, ucols)
1303 {
1304 char *u_colname = strVal(lfirst(ucol));
1305 ListCell *col;
1306 int ndx;
1307 int l_index = -1;
1308 int r_index = -1;
1309 Var *l_colvar,
1310 *r_colvar;
1311 Node *u_colvar;
1312 ParseNamespaceColumn *res_nscolumn;
1313
1314 Assert(u_colname[0] != '\0');
1315
1316 /* Check for USING(foo,foo) */
1317 foreach(col, res_colnames)
1318 {
1319 char *res_colname = strVal(lfirst(col));
1320
1321 if (strcmp(res_colname, u_colname) == 0)
1322 ereport(ERROR,
1323 (errcode(ERRCODE_DUPLICATE_COLUMN),
1324 errmsg("column name \"%s\" appears more than once in USING clause",
1325 u_colname)));
1326 }
1327
1328 /* Find it in left input */
1329 ndx = 0;
1330 foreach(col, l_colnames)
1331 {
1332 char *l_colname = strVal(lfirst(col));
1333
1334 if (strcmp(l_colname, u_colname) == 0)
1335 {
1336 if (l_index >= 0)
1337 ereport(ERROR,
1338 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
1339 errmsg("common column name \"%s\" appears more than once in left table",
1340 u_colname)));
1341 l_index = ndx;
1342 }
1343 ndx++;
1344 }
1345 if (l_index < 0)
1346 ereport(ERROR,
1347 (errcode(ERRCODE_UNDEFINED_COLUMN),
1348 errmsg("column \"%s\" specified in USING clause does not exist in left table",
1349 u_colname)));
1350 l_colnos = lappend_int(l_colnos, l_index + 1);
1351
1352 /* Find it in right input */
1353 ndx = 0;
1354 foreach(col, r_colnames)
1355 {
1356 char *r_colname = strVal(lfirst(col));
1357
1358 if (strcmp(r_colname, u_colname) == 0)
1359 {
1360 if (r_index >= 0)
1361 ereport(ERROR,
1362 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
1363 errmsg("common column name \"%s\" appears more than once in right table",
1364 u_colname)));
1365 r_index = ndx;
1366 }
1367 ndx++;
1368 }
1369 if (r_index < 0)
1370 ereport(ERROR,
1371 (errcode(ERRCODE_UNDEFINED_COLUMN),
1372 errmsg("column \"%s\" specified in USING clause does not exist in right table",
1373 u_colname)));
1374 r_colnos = lappend_int(r_colnos, r_index + 1);
1375
1376 l_colvar = buildVarFromNSColumn(l_nscolumns + l_index);
1377 l_usingvars = lappend(l_usingvars, l_colvar);
1378 r_colvar = buildVarFromNSColumn(r_nscolumns + r_index);
1379 r_usingvars = lappend(r_usingvars, r_colvar);
1380
1381 res_colnames = lappend(res_colnames, lfirst(ucol));
1382 u_colvar = buildMergedJoinVar(pstate,
1383 j->jointype,
1384 l_colvar,
1385 r_colvar);
1386 res_colvars = lappend(res_colvars, u_colvar);
1387 res_nscolumn = res_nscolumns + res_colindex;
1388 res_colindex++;
1389 if (u_colvar == (Node *) l_colvar)
1390 {
1391 /* Merged column is equivalent to left input */
1392 *res_nscolumn = l_nscolumns[l_index];
1393 }
1394 else if (u_colvar == (Node *) r_colvar)
1395 {
1396 /* Merged column is equivalent to right input */
1397 *res_nscolumn = r_nscolumns[r_index];
1398 }
1399 else
1400 {
1401 /*
1402 * Merged column is not semantically equivalent to either
1403 * input, so it needs to be referenced as the join output
1404 * column. We don't know the join's varno yet, so we'll
1405 * replace these zeroes below.
1406 */
1407 res_nscolumn->p_varno = 0;
1408 res_nscolumn->p_varattno = res_colindex;
1409 res_nscolumn->p_vartype = exprType(u_colvar);
1410 res_nscolumn->p_vartypmod = exprTypmod(u_colvar);
1411 res_nscolumn->p_varcollid = exprCollation(u_colvar);
1412 res_nscolumn->p_varnosyn = 0;
1413 res_nscolumn->p_varattnosyn = res_colindex;
1414 }
1415 }
1416
1417 j->quals = transformJoinUsingClause(pstate,
1418 l_usingvars,
1419 r_usingvars);
1420 }
1421 else if (j->quals)
1422 {
1423 /* User-written ON-condition; transform it */
1424 j->quals = transformJoinOnClause(pstate, j, my_namespace);
1425 }
1426 else
1427 {
1428 /* CROSS JOIN: no quals */
1429 }
1430
1431 /* Add remaining columns from each side to the output columns */
1432 res_colindex +=
1433 extractRemainingColumns(l_nscolumns, l_colnames, &l_colnos,
1434 &res_colnames, &res_colvars,
1435 res_nscolumns + res_colindex);
1436 res_colindex +=
1437 extractRemainingColumns(r_nscolumns, r_colnames, &r_colnos,
1438 &res_colnames, &res_colvars,
1439 res_nscolumns + res_colindex);
1440
1441 /*
1442 * Check alias (AS clause), if any.
1443 */
1444 if (j->alias)
1445 {
1446 if (j->alias->colnames != NIL)
1447 {
1448 if (list_length(j->alias->colnames) > list_length(res_colnames))
1449 ereport(ERROR,
1450 (errcode(ERRCODE_SYNTAX_ERROR),
1451 errmsg("column alias list for \"%s\" has too many entries",
1452 j->alias->aliasname)));
1453 }
1454 }
1455
1456 /*
1457 * Now build an RTE and nsitem for the result of the join.
1458 * res_nscolumns isn't totally done yet, but that's OK because
1459 * addRangeTableEntryForJoin doesn't examine it, only store a pointer.
1460 */
1461 nsitem = addRangeTableEntryForJoin(pstate,
1462 res_colnames,
1463 res_nscolumns,
1464 j->jointype,
1465 list_length(j->usingClause),
1466 res_colvars,
1467 l_colnos,
1468 r_colnos,
1469 j->join_using_alias,
1470 j->alias,
1471 true);
1472
1473 j->rtindex = nsitem->p_rtindex;
1474
1475 /*
1476 * Now that we know the join RTE's rangetable index, we can fix up the
1477 * res_nscolumns data in places where it should contain that.
1478 */
1479 Assert(res_colindex == list_length(nsitem->p_names->colnames));
1480 for (k = 0; k < res_colindex; k++)
1481 {
1482 ParseNamespaceColumn *nscol = res_nscolumns + k;
1483
1484 /* fill in join RTI for merged columns */
1485 if (nscol->p_varno == 0)
1486 nscol->p_varno = j->rtindex;
1487 if (nscol->p_varnosyn == 0)
1488 nscol->p_varnosyn = j->rtindex;
1489 /* if join has an alias, it syntactically hides all inputs */
1490 if (j->alias)
1491 {
1492 nscol->p_varnosyn = j->rtindex;
1493 nscol->p_varattnosyn = k + 1;
1494 }
1495 }
1496
1497 /* make a matching link to the JoinExpr for later use */
1498 for (k = list_length(pstate->p_joinexprs) + 1; k < j->rtindex; k++)
1499 pstate->p_joinexprs = lappend(pstate->p_joinexprs, NULL);
1500 pstate->p_joinexprs = lappend(pstate->p_joinexprs, j);
1501 Assert(list_length(pstate->p_joinexprs) == j->rtindex);
1502
1503 /*
1504 * If the join has a USING alias, build a ParseNamespaceItem for that
1505 * and add it to the list of nsitems in the join's input.
1506 */
1507 if (j->join_using_alias)
1508 {
1509 ParseNamespaceItem *jnsitem;
1510
1511 jnsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
1512 jnsitem->p_names = j->join_using_alias;
1513 jnsitem->p_rte = nsitem->p_rte;
1514 jnsitem->p_rtindex = nsitem->p_rtindex;
1515 /* no need to copy the first N columns, just use res_nscolumns */
1516 jnsitem->p_nscolumns = res_nscolumns;
1517 /* set default visibility flags; might get changed later */
1518 jnsitem->p_rel_visible = true;
1519 jnsitem->p_cols_visible = true;
1520 jnsitem->p_lateral_only = false;
1521 jnsitem->p_lateral_ok = true;
1522 /* Per SQL, we must check for alias conflicts */
1523 checkNameSpaceConflicts(pstate, list_make1(jnsitem), my_namespace);
1524 my_namespace = lappend(my_namespace, jnsitem);
1525 }
1526
1527 /*
1528 * Prepare returned namespace list. If the JOIN has an alias then it
1529 * hides the contained RTEs completely; otherwise, the contained RTEs
1530 * are still visible as table names, but are not visible for
1531 * unqualified column-name access.
1532 *
1533 * Note: if there are nested alias-less JOINs, the lower-level ones
1534 * will remain in the list although they have neither p_rel_visible
1535 * nor p_cols_visible set. We could delete such list items, but it's
1536 * unclear that it's worth expending cycles to do so.
1537 */
1538 if (j->alias != NULL)
1539 my_namespace = NIL;
1540 else
1541 setNamespaceColumnVisibility(my_namespace, false);
1542
1543 /*
1544 * The join RTE itself is always made visible for unqualified column
1545 * names. It's visible as a relation name only if it has an alias.
1546 */
1547 nsitem->p_rel_visible = (j->alias != NULL);
1548 nsitem->p_cols_visible = true;
1549 nsitem->p_lateral_only = false;
1550 nsitem->p_lateral_ok = true;
1551
1552 *top_nsitem = nsitem;
1553 *namespace = lappend(my_namespace, nsitem);
1554
1555 return (Node *) j;
1556 }
1557 else
1558 elog(ERROR, "unrecognized node type: %d", (int) nodeTag(n));
1559 return NULL; /* can't get here, keep compiler quiet */
1560 }
1561
1562 /*
1563 * buildVarFromNSColumn -
1564 * build a Var node using ParseNamespaceColumn data
1565 *
1566 * We assume varlevelsup should be 0, and no location is specified
1567 */
1568 static Var *
buildVarFromNSColumn(ParseNamespaceColumn * nscol)1569 buildVarFromNSColumn(ParseNamespaceColumn *nscol)
1570 {
1571 Var *var;
1572
1573 Assert(nscol->p_varno > 0); /* i.e., not deleted column */
1574 var = makeVar(nscol->p_varno,
1575 nscol->p_varattno,
1576 nscol->p_vartype,
1577 nscol->p_vartypmod,
1578 nscol->p_varcollid,
1579 0);
1580 /* makeVar doesn't offer parameters for these, so set by hand: */
1581 var->varnosyn = nscol->p_varnosyn;
1582 var->varattnosyn = nscol->p_varattnosyn;
1583 return var;
1584 }
1585
1586 /*
1587 * buildMergedJoinVar -
1588 * generate a suitable replacement expression for a merged join column
1589 */
1590 static Node *
buildMergedJoinVar(ParseState * pstate,JoinType jointype,Var * l_colvar,Var * r_colvar)1591 buildMergedJoinVar(ParseState *pstate, JoinType jointype,
1592 Var *l_colvar, Var *r_colvar)
1593 {
1594 Oid outcoltype;
1595 int32 outcoltypmod;
1596 Node *l_node,
1597 *r_node,
1598 *res_node;
1599
1600 outcoltype = select_common_type(pstate,
1601 list_make2(l_colvar, r_colvar),
1602 "JOIN/USING",
1603 NULL);
1604 outcoltypmod = select_common_typmod(pstate,
1605 list_make2(l_colvar, r_colvar),
1606 outcoltype);
1607
1608 /*
1609 * Insert coercion functions if needed. Note that a difference in typmod
1610 * can only happen if input has typmod but outcoltypmod is -1. In that
1611 * case we insert a RelabelType to clearly mark that result's typmod is
1612 * not same as input. We never need coerce_type_typmod.
1613 */
1614 if (l_colvar->vartype != outcoltype)
1615 l_node = coerce_type(pstate, (Node *) l_colvar, l_colvar->vartype,
1616 outcoltype, outcoltypmod,
1617 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
1618 else if (l_colvar->vartypmod != outcoltypmod)
1619 l_node = (Node *) makeRelabelType((Expr *) l_colvar,
1620 outcoltype, outcoltypmod,
1621 InvalidOid, /* fixed below */
1622 COERCE_IMPLICIT_CAST);
1623 else
1624 l_node = (Node *) l_colvar;
1625
1626 if (r_colvar->vartype != outcoltype)
1627 r_node = coerce_type(pstate, (Node *) r_colvar, r_colvar->vartype,
1628 outcoltype, outcoltypmod,
1629 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
1630 else if (r_colvar->vartypmod != outcoltypmod)
1631 r_node = (Node *) makeRelabelType((Expr *) r_colvar,
1632 outcoltype, outcoltypmod,
1633 InvalidOid, /* fixed below */
1634 COERCE_IMPLICIT_CAST);
1635 else
1636 r_node = (Node *) r_colvar;
1637
1638 /*
1639 * Choose what to emit
1640 */
1641 switch (jointype)
1642 {
1643 case JOIN_INNER:
1644
1645 /*
1646 * We can use either var; prefer non-coerced one if available.
1647 */
1648 if (IsA(l_node, Var))
1649 res_node = l_node;
1650 else if (IsA(r_node, Var))
1651 res_node = r_node;
1652 else
1653 res_node = l_node;
1654 break;
1655 case JOIN_LEFT:
1656 /* Always use left var */
1657 res_node = l_node;
1658 break;
1659 case JOIN_RIGHT:
1660 /* Always use right var */
1661 res_node = r_node;
1662 break;
1663 case JOIN_FULL:
1664 {
1665 /*
1666 * Here we must build a COALESCE expression to ensure that the
1667 * join output is non-null if either input is.
1668 */
1669 CoalesceExpr *c = makeNode(CoalesceExpr);
1670
1671 c->coalescetype = outcoltype;
1672 /* coalescecollid will get set below */
1673 c->args = list_make2(l_node, r_node);
1674 c->location = -1;
1675 res_node = (Node *) c;
1676 break;
1677 }
1678 default:
1679 elog(ERROR, "unrecognized join type: %d", (int) jointype);
1680 res_node = NULL; /* keep compiler quiet */
1681 break;
1682 }
1683
1684 /*
1685 * Apply assign_expr_collations to fix up the collation info in the
1686 * coercion and CoalesceExpr nodes, if we made any. This must be done now
1687 * so that the join node's alias vars show correct collation info.
1688 */
1689 assign_expr_collations(pstate, res_node);
1690
1691 return res_node;
1692 }
1693
1694 /*
1695 * setNamespaceColumnVisibility -
1696 * Convenience subroutine to update cols_visible flags in a namespace list.
1697 */
1698 static void
setNamespaceColumnVisibility(List * namespace,bool cols_visible)1699 setNamespaceColumnVisibility(List *namespace, bool cols_visible)
1700 {
1701 ListCell *lc;
1702
1703 foreach(lc, namespace)
1704 {
1705 ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(lc);
1706
1707 nsitem->p_cols_visible = cols_visible;
1708 }
1709 }
1710
1711 /*
1712 * setNamespaceLateralState -
1713 * Convenience subroutine to update LATERAL flags in a namespace list.
1714 */
1715 static void
setNamespaceLateralState(List * namespace,bool lateral_only,bool lateral_ok)1716 setNamespaceLateralState(List *namespace, bool lateral_only, bool lateral_ok)
1717 {
1718 ListCell *lc;
1719
1720 foreach(lc, namespace)
1721 {
1722 ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(lc);
1723
1724 nsitem->p_lateral_only = lateral_only;
1725 nsitem->p_lateral_ok = lateral_ok;
1726 }
1727 }
1728
1729
1730 /*
1731 * transformWhereClause -
1732 * Transform the qualification and make sure it is of type boolean.
1733 * Used for WHERE and allied clauses.
1734 *
1735 * constructName does not affect the semantics, but is used in error messages
1736 */
1737 Node *
transformWhereClause(ParseState * pstate,Node * clause,ParseExprKind exprKind,const char * constructName)1738 transformWhereClause(ParseState *pstate, Node *clause,
1739 ParseExprKind exprKind, const char *constructName)
1740 {
1741 Node *qual;
1742
1743 if (clause == NULL)
1744 return NULL;
1745
1746 qual = transformExpr(pstate, clause, exprKind);
1747
1748 qual = coerce_to_boolean(pstate, qual, constructName);
1749
1750 return qual;
1751 }
1752
1753
1754 /*
1755 * transformLimitClause -
1756 * Transform the expression and make sure it is of type bigint.
1757 * Used for LIMIT and allied clauses.
1758 *
1759 * Note: as of Postgres 8.2, LIMIT expressions are expected to yield int8,
1760 * rather than int4 as before.
1761 *
1762 * constructName does not affect the semantics, but is used in error messages
1763 */
1764 Node *
transformLimitClause(ParseState * pstate,Node * clause,ParseExprKind exprKind,const char * constructName,LimitOption limitOption)1765 transformLimitClause(ParseState *pstate, Node *clause,
1766 ParseExprKind exprKind, const char *constructName,
1767 LimitOption limitOption)
1768 {
1769 Node *qual;
1770
1771 if (clause == NULL)
1772 return NULL;
1773
1774 qual = transformExpr(pstate, clause, exprKind);
1775
1776 qual = coerce_to_specific_type(pstate, qual, INT8OID, constructName);
1777
1778 /* LIMIT can't refer to any variables of the current query */
1779 checkExprIsVarFree(pstate, qual, constructName);
1780
1781 /*
1782 * Don't allow NULLs in FETCH FIRST .. WITH TIES. This test is ugly and
1783 * extremely simplistic, in that you can pass a NULL anyway by hiding it
1784 * inside an expression -- but this protects ruleutils against emitting an
1785 * unadorned NULL that's not accepted back by the grammar.
1786 */
1787 if (exprKind == EXPR_KIND_LIMIT && limitOption == LIMIT_OPTION_WITH_TIES &&
1788 IsA(clause, A_Const) && ((A_Const *) clause)->val.type == T_Null)
1789 ereport(ERROR,
1790 (errcode(ERRCODE_INVALID_ROW_COUNT_IN_LIMIT_CLAUSE),
1791 errmsg("row count cannot be null in FETCH FIRST ... WITH TIES clause")));
1792
1793 return qual;
1794 }
1795
1796 /*
1797 * checkExprIsVarFree
1798 * Check that given expr has no Vars of the current query level
1799 * (aggregates and window functions should have been rejected already).
1800 *
1801 * This is used to check expressions that have to have a consistent value
1802 * across all rows of the query, such as a LIMIT. Arguably it should reject
1803 * volatile functions, too, but we don't do that --- whatever value the
1804 * function gives on first execution is what you get.
1805 *
1806 * constructName does not affect the semantics, but is used in error messages
1807 */
1808 static void
checkExprIsVarFree(ParseState * pstate,Node * n,const char * constructName)1809 checkExprIsVarFree(ParseState *pstate, Node *n, const char *constructName)
1810 {
1811 if (contain_vars_of_level(n, 0))
1812 {
1813 ereport(ERROR,
1814 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
1815 /* translator: %s is name of a SQL construct, eg LIMIT */
1816 errmsg("argument of %s must not contain variables",
1817 constructName),
1818 parser_errposition(pstate,
1819 locate_var_of_level(n, 0))));
1820 }
1821 }
1822
1823
1824 /*
1825 * checkTargetlistEntrySQL92 -
1826 * Validate a targetlist entry found by findTargetlistEntrySQL92
1827 *
1828 * When we select a pre-existing tlist entry as a result of syntax such
1829 * as "GROUP BY 1", we have to make sure it is acceptable for use in the
1830 * indicated clause type; transformExpr() will have treated it as a regular
1831 * targetlist item.
1832 */
1833 static void
checkTargetlistEntrySQL92(ParseState * pstate,TargetEntry * tle,ParseExprKind exprKind)1834 checkTargetlistEntrySQL92(ParseState *pstate, TargetEntry *tle,
1835 ParseExprKind exprKind)
1836 {
1837 switch (exprKind)
1838 {
1839 case EXPR_KIND_GROUP_BY:
1840 /* reject aggregates and window functions */
1841 if (pstate->p_hasAggs &&
1842 contain_aggs_of_level((Node *) tle->expr, 0))
1843 ereport(ERROR,
1844 (errcode(ERRCODE_GROUPING_ERROR),
1845 /* translator: %s is name of a SQL construct, eg GROUP BY */
1846 errmsg("aggregate functions are not allowed in %s",
1847 ParseExprKindName(exprKind)),
1848 parser_errposition(pstate,
1849 locate_agg_of_level((Node *) tle->expr, 0))));
1850 if (pstate->p_hasWindowFuncs &&
1851 contain_windowfuncs((Node *) tle->expr))
1852 ereport(ERROR,
1853 (errcode(ERRCODE_WINDOWING_ERROR),
1854 /* translator: %s is name of a SQL construct, eg GROUP BY */
1855 errmsg("window functions are not allowed in %s",
1856 ParseExprKindName(exprKind)),
1857 parser_errposition(pstate,
1858 locate_windowfunc((Node *) tle->expr))));
1859 break;
1860 case EXPR_KIND_ORDER_BY:
1861 /* no extra checks needed */
1862 break;
1863 case EXPR_KIND_DISTINCT_ON:
1864 /* no extra checks needed */
1865 break;
1866 default:
1867 elog(ERROR, "unexpected exprKind in checkTargetlistEntrySQL92");
1868 break;
1869 }
1870 }
1871
1872 /*
1873 * findTargetlistEntrySQL92 -
1874 * Returns the targetlist entry matching the given (untransformed) node.
1875 * If no matching entry exists, one is created and appended to the target
1876 * list as a "resjunk" node.
1877 *
1878 * This function supports the old SQL92 ORDER BY interpretation, where the
1879 * expression is an output column name or number. If we fail to find a
1880 * match of that sort, we fall through to the SQL99 rules. For historical
1881 * reasons, Postgres also allows this interpretation for GROUP BY, though
1882 * the standard never did. However, for GROUP BY we prefer a SQL99 match.
1883 * This function is *not* used for WINDOW definitions.
1884 *
1885 * node the ORDER BY, GROUP BY, or DISTINCT ON expression to be matched
1886 * tlist the target list (passed by reference so we can append to it)
1887 * exprKind identifies clause type being processed
1888 */
1889 static TargetEntry *
findTargetlistEntrySQL92(ParseState * pstate,Node * node,List ** tlist,ParseExprKind exprKind)1890 findTargetlistEntrySQL92(ParseState *pstate, Node *node, List **tlist,
1891 ParseExprKind exprKind)
1892 {
1893 ListCell *tl;
1894
1895 /*----------
1896 * Handle two special cases as mandated by the SQL92 spec:
1897 *
1898 * 1. Bare ColumnName (no qualifier or subscripts)
1899 * For a bare identifier, we search for a matching column name
1900 * in the existing target list. Multiple matches are an error
1901 * unless they refer to identical values; for example,
1902 * we allow SELECT a, a FROM table ORDER BY a
1903 * but not SELECT a AS b, b FROM table ORDER BY b
1904 * If no match is found, we fall through and treat the identifier
1905 * as an expression.
1906 * For GROUP BY, it is incorrect to match the grouping item against
1907 * targetlist entries: according to SQL92, an identifier in GROUP BY
1908 * is a reference to a column name exposed by FROM, not to a target
1909 * list column. However, many implementations (including pre-7.0
1910 * PostgreSQL) accept this anyway. So for GROUP BY, we look first
1911 * to see if the identifier matches any FROM column name, and only
1912 * try for a targetlist name if it doesn't. This ensures that we
1913 * adhere to the spec in the case where the name could be both.
1914 * DISTINCT ON isn't in the standard, so we can do what we like there;
1915 * we choose to make it work like ORDER BY, on the rather flimsy
1916 * grounds that ordinary DISTINCT works on targetlist entries.
1917 *
1918 * 2. IntegerConstant
1919 * This means to use the n'th item in the existing target list.
1920 * Note that it would make no sense to order/group/distinct by an
1921 * actual constant, so this does not create a conflict with SQL99.
1922 * GROUP BY column-number is not allowed by SQL92, but since
1923 * the standard has no other behavior defined for this syntax,
1924 * we may as well accept this common extension.
1925 *
1926 * Note that pre-existing resjunk targets must not be used in either case,
1927 * since the user didn't write them in his SELECT list.
1928 *
1929 * If neither special case applies, fall through to treat the item as
1930 * an expression per SQL99.
1931 *----------
1932 */
1933 if (IsA(node, ColumnRef) &&
1934 list_length(((ColumnRef *) node)->fields) == 1 &&
1935 IsA(linitial(((ColumnRef *) node)->fields), String))
1936 {
1937 char *name = strVal(linitial(((ColumnRef *) node)->fields));
1938 int location = ((ColumnRef *) node)->location;
1939
1940 if (exprKind == EXPR_KIND_GROUP_BY)
1941 {
1942 /*
1943 * In GROUP BY, we must prefer a match against a FROM-clause
1944 * column to one against the targetlist. Look to see if there is
1945 * a matching column. If so, fall through to use SQL99 rules.
1946 * NOTE: if name could refer ambiguously to more than one column
1947 * name exposed by FROM, colNameToVar will ereport(ERROR). That's
1948 * just what we want here.
1949 *
1950 * Small tweak for 7.4.3: ignore matches in upper query levels.
1951 * This effectively changes the search order for bare names to (1)
1952 * local FROM variables, (2) local targetlist aliases, (3) outer
1953 * FROM variables, whereas before it was (1) (3) (2). SQL92 and
1954 * SQL99 do not allow GROUPing BY an outer reference, so this
1955 * breaks no cases that are legal per spec, and it seems a more
1956 * self-consistent behavior.
1957 */
1958 if (colNameToVar(pstate, name, true, location) != NULL)
1959 name = NULL;
1960 }
1961
1962 if (name != NULL)
1963 {
1964 TargetEntry *target_result = NULL;
1965
1966 foreach(tl, *tlist)
1967 {
1968 TargetEntry *tle = (TargetEntry *) lfirst(tl);
1969
1970 if (!tle->resjunk &&
1971 strcmp(tle->resname, name) == 0)
1972 {
1973 if (target_result != NULL)
1974 {
1975 if (!equal(target_result->expr, tle->expr))
1976 ereport(ERROR,
1977 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
1978
1979 /*------
1980 translator: first %s is name of a SQL construct, eg ORDER BY */
1981 errmsg("%s \"%s\" is ambiguous",
1982 ParseExprKindName(exprKind),
1983 name),
1984 parser_errposition(pstate, location)));
1985 }
1986 else
1987 target_result = tle;
1988 /* Stay in loop to check for ambiguity */
1989 }
1990 }
1991 if (target_result != NULL)
1992 {
1993 /* return the first match, after suitable validation */
1994 checkTargetlistEntrySQL92(pstate, target_result, exprKind);
1995 return target_result;
1996 }
1997 }
1998 }
1999 if (IsA(node, A_Const))
2000 {
2001 Value *val = &((A_Const *) node)->val;
2002 int location = ((A_Const *) node)->location;
2003 int targetlist_pos = 0;
2004 int target_pos;
2005
2006 if (!IsA(val, Integer))
2007 ereport(ERROR,
2008 (errcode(ERRCODE_SYNTAX_ERROR),
2009 /* translator: %s is name of a SQL construct, eg ORDER BY */
2010 errmsg("non-integer constant in %s",
2011 ParseExprKindName(exprKind)),
2012 parser_errposition(pstate, location)));
2013
2014 target_pos = intVal(val);
2015 foreach(tl, *tlist)
2016 {
2017 TargetEntry *tle = (TargetEntry *) lfirst(tl);
2018
2019 if (!tle->resjunk)
2020 {
2021 if (++targetlist_pos == target_pos)
2022 {
2023 /* return the unique match, after suitable validation */
2024 checkTargetlistEntrySQL92(pstate, tle, exprKind);
2025 return tle;
2026 }
2027 }
2028 }
2029 ereport(ERROR,
2030 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
2031 /* translator: %s is name of a SQL construct, eg ORDER BY */
2032 errmsg("%s position %d is not in select list",
2033 ParseExprKindName(exprKind), target_pos),
2034 parser_errposition(pstate, location)));
2035 }
2036
2037 /*
2038 * Otherwise, we have an expression, so process it per SQL99 rules.
2039 */
2040 return findTargetlistEntrySQL99(pstate, node, tlist, exprKind);
2041 }
2042
2043 /*
2044 * findTargetlistEntrySQL99 -
2045 * Returns the targetlist entry matching the given (untransformed) node.
2046 * If no matching entry exists, one is created and appended to the target
2047 * list as a "resjunk" node.
2048 *
2049 * This function supports the SQL99 interpretation, wherein the expression
2050 * is just an ordinary expression referencing input column names.
2051 *
2052 * node the ORDER BY, GROUP BY, etc expression to be matched
2053 * tlist the target list (passed by reference so we can append to it)
2054 * exprKind identifies clause type being processed
2055 */
2056 static TargetEntry *
findTargetlistEntrySQL99(ParseState * pstate,Node * node,List ** tlist,ParseExprKind exprKind)2057 findTargetlistEntrySQL99(ParseState *pstate, Node *node, List **tlist,
2058 ParseExprKind exprKind)
2059 {
2060 TargetEntry *target_result;
2061 ListCell *tl;
2062 Node *expr;
2063
2064 /*
2065 * Convert the untransformed node to a transformed expression, and search
2066 * for a match in the tlist. NOTE: it doesn't really matter whether there
2067 * is more than one match. Also, we are willing to match an existing
2068 * resjunk target here, though the SQL92 cases above must ignore resjunk
2069 * targets.
2070 */
2071 expr = transformExpr(pstate, node, exprKind);
2072
2073 foreach(tl, *tlist)
2074 {
2075 TargetEntry *tle = (TargetEntry *) lfirst(tl);
2076 Node *texpr;
2077
2078 /*
2079 * Ignore any implicit cast on the existing tlist expression.
2080 *
2081 * This essentially allows the ORDER/GROUP/etc item to adopt the same
2082 * datatype previously selected for a textually-equivalent tlist item.
2083 * There can't be any implicit cast at top level in an ordinary SELECT
2084 * tlist at this stage, but the case does arise with ORDER BY in an
2085 * aggregate function.
2086 */
2087 texpr = strip_implicit_coercions((Node *) tle->expr);
2088
2089 if (equal(expr, texpr))
2090 return tle;
2091 }
2092
2093 /*
2094 * If no matches, construct a new target entry which is appended to the
2095 * end of the target list. This target is given resjunk = true so that it
2096 * will not be projected into the final tuple.
2097 */
2098 target_result = transformTargetEntry(pstate, node, expr, exprKind,
2099 NULL, true);
2100
2101 *tlist = lappend(*tlist, target_result);
2102
2103 return target_result;
2104 }
2105
2106 /*-------------------------------------------------------------------------
2107 * Flatten out parenthesized sublists in grouping lists, and some cases
2108 * of nested grouping sets.
2109 *
2110 * Inside a grouping set (ROLLUP, CUBE, or GROUPING SETS), we expect the
2111 * content to be nested no more than 2 deep: i.e. ROLLUP((a,b),(c,d)) is
2112 * ok, but ROLLUP((a,(b,c)),d) is flattened to ((a,b,c),d), which we then
2113 * (later) normalize to ((a,b,c),(d)).
2114 *
2115 * CUBE or ROLLUP can be nested inside GROUPING SETS (but not the reverse),
2116 * and we leave that alone if we find it. But if we see GROUPING SETS inside
2117 * GROUPING SETS, we can flatten and normalize as follows:
2118 * GROUPING SETS (a, (b,c), GROUPING SETS ((c,d),(e)), (f,g))
2119 * becomes
2120 * GROUPING SETS ((a), (b,c), (c,d), (e), (f,g))
2121 *
2122 * This is per the spec's syntax transformations, but these are the only such
2123 * transformations we do in parse analysis, so that queries retain the
2124 * originally specified grouping set syntax for CUBE and ROLLUP as much as
2125 * possible when deparsed. (Full expansion of the result into a list of
2126 * grouping sets is left to the planner.)
2127 *
2128 * When we're done, the resulting list should contain only these possible
2129 * elements:
2130 * - an expression
2131 * - a CUBE or ROLLUP with a list of expressions nested 2 deep
2132 * - a GROUPING SET containing any of:
2133 * - expression lists
2134 * - empty grouping sets
2135 * - CUBE or ROLLUP nodes with lists nested 2 deep
2136 * The return is a new list, but doesn't deep-copy the old nodes except for
2137 * GroupingSet nodes.
2138 *
2139 * As a side effect, flag whether the list has any GroupingSet nodes.
2140 *-------------------------------------------------------------------------
2141 */
2142 static Node *
flatten_grouping_sets(Node * expr,bool toplevel,bool * hasGroupingSets)2143 flatten_grouping_sets(Node *expr, bool toplevel, bool *hasGroupingSets)
2144 {
2145 /* just in case of pathological input */
2146 check_stack_depth();
2147
2148 if (expr == (Node *) NIL)
2149 return (Node *) NIL;
2150
2151 switch (expr->type)
2152 {
2153 case T_RowExpr:
2154 {
2155 RowExpr *r = (RowExpr *) expr;
2156
2157 if (r->row_format == COERCE_IMPLICIT_CAST)
2158 return flatten_grouping_sets((Node *) r->args,
2159 false, NULL);
2160 }
2161 break;
2162 case T_GroupingSet:
2163 {
2164 GroupingSet *gset = (GroupingSet *) expr;
2165 ListCell *l2;
2166 List *result_set = NIL;
2167
2168 if (hasGroupingSets)
2169 *hasGroupingSets = true;
2170
2171 /*
2172 * at the top level, we skip over all empty grouping sets; the
2173 * caller can supply the canonical GROUP BY () if nothing is
2174 * left.
2175 */
2176
2177 if (toplevel && gset->kind == GROUPING_SET_EMPTY)
2178 return (Node *) NIL;
2179
2180 foreach(l2, gset->content)
2181 {
2182 Node *n1 = lfirst(l2);
2183 Node *n2 = flatten_grouping_sets(n1, false, NULL);
2184
2185 if (IsA(n1, GroupingSet) &&
2186 ((GroupingSet *) n1)->kind == GROUPING_SET_SETS)
2187 result_set = list_concat(result_set, (List *) n2);
2188 else
2189 result_set = lappend(result_set, n2);
2190 }
2191
2192 /*
2193 * At top level, keep the grouping set node; but if we're in a
2194 * nested grouping set, then we need to concat the flattened
2195 * result into the outer list if it's simply nested.
2196 */
2197
2198 if (toplevel || (gset->kind != GROUPING_SET_SETS))
2199 {
2200 return (Node *) makeGroupingSet(gset->kind, result_set, gset->location);
2201 }
2202 else
2203 return (Node *) result_set;
2204 }
2205 case T_List:
2206 {
2207 List *result = NIL;
2208 ListCell *l;
2209
2210 foreach(l, (List *) expr)
2211 {
2212 Node *n = flatten_grouping_sets(lfirst(l), toplevel, hasGroupingSets);
2213
2214 if (n != (Node *) NIL)
2215 {
2216 if (IsA(n, List))
2217 result = list_concat(result, (List *) n);
2218 else
2219 result = lappend(result, n);
2220 }
2221 }
2222
2223 return (Node *) result;
2224 }
2225 default:
2226 break;
2227 }
2228
2229 return expr;
2230 }
2231
2232 /*
2233 * Transform a single expression within a GROUP BY clause or grouping set.
2234 *
2235 * The expression is added to the targetlist if not already present, and to the
2236 * flatresult list (which will become the groupClause) if not already present
2237 * there. The sortClause is consulted for operator and sort order hints.
2238 *
2239 * Returns the ressortgroupref of the expression.
2240 *
2241 * flatresult reference to flat list of SortGroupClause nodes
2242 * seen_local bitmapset of sortgrouprefs already seen at the local level
2243 * pstate ParseState
2244 * gexpr node to transform
2245 * targetlist reference to TargetEntry list
2246 * sortClause ORDER BY clause (SortGroupClause nodes)
2247 * exprKind expression kind
2248 * useSQL99 SQL99 rather than SQL92 syntax
2249 * toplevel false if within any grouping set
2250 */
2251 static Index
transformGroupClauseExpr(List ** flatresult,Bitmapset * seen_local,ParseState * pstate,Node * gexpr,List ** targetlist,List * sortClause,ParseExprKind exprKind,bool useSQL99,bool toplevel)2252 transformGroupClauseExpr(List **flatresult, Bitmapset *seen_local,
2253 ParseState *pstate, Node *gexpr,
2254 List **targetlist, List *sortClause,
2255 ParseExprKind exprKind, bool useSQL99, bool toplevel)
2256 {
2257 TargetEntry *tle;
2258 bool found = false;
2259
2260 if (useSQL99)
2261 tle = findTargetlistEntrySQL99(pstate, gexpr,
2262 targetlist, exprKind);
2263 else
2264 tle = findTargetlistEntrySQL92(pstate, gexpr,
2265 targetlist, exprKind);
2266
2267 if (tle->ressortgroupref > 0)
2268 {
2269 ListCell *sl;
2270
2271 /*
2272 * Eliminate duplicates (GROUP BY x, x) but only at local level.
2273 * (Duplicates in grouping sets can affect the number of returned
2274 * rows, so can't be dropped indiscriminately.)
2275 *
2276 * Since we don't care about anything except the sortgroupref, we can
2277 * use a bitmapset rather than scanning lists.
2278 */
2279 if (bms_is_member(tle->ressortgroupref, seen_local))
2280 return 0;
2281
2282 /*
2283 * If we're already in the flat clause list, we don't need to consider
2284 * adding ourselves again.
2285 */
2286 found = targetIsInSortList(tle, InvalidOid, *flatresult);
2287 if (found)
2288 return tle->ressortgroupref;
2289
2290 /*
2291 * If the GROUP BY tlist entry also appears in ORDER BY, copy operator
2292 * info from the (first) matching ORDER BY item. This means that if
2293 * you write something like "GROUP BY foo ORDER BY foo USING <<<", the
2294 * GROUP BY operation silently takes on the equality semantics implied
2295 * by the ORDER BY. There are two reasons to do this: it improves the
2296 * odds that we can implement both GROUP BY and ORDER BY with a single
2297 * sort step, and it allows the user to choose the equality semantics
2298 * used by GROUP BY, should she be working with a datatype that has
2299 * more than one equality operator.
2300 *
2301 * If we're in a grouping set, though, we force our requested ordering
2302 * to be NULLS LAST, because if we have any hope of using a sorted agg
2303 * for the job, we're going to be tacking on generated NULL values
2304 * after the corresponding groups. If the user demands nulls first,
2305 * another sort step is going to be inevitable, but that's the
2306 * planner's problem.
2307 */
2308
2309 foreach(sl, sortClause)
2310 {
2311 SortGroupClause *sc = (SortGroupClause *) lfirst(sl);
2312
2313 if (sc->tleSortGroupRef == tle->ressortgroupref)
2314 {
2315 SortGroupClause *grpc = copyObject(sc);
2316
2317 if (!toplevel)
2318 grpc->nulls_first = false;
2319 *flatresult = lappend(*flatresult, grpc);
2320 found = true;
2321 break;
2322 }
2323 }
2324 }
2325
2326 /*
2327 * If no match in ORDER BY, just add it to the result using default
2328 * sort/group semantics.
2329 */
2330 if (!found)
2331 *flatresult = addTargetToGroupList(pstate, tle,
2332 *flatresult, *targetlist,
2333 exprLocation(gexpr));
2334
2335 /*
2336 * _something_ must have assigned us a sortgroupref by now...
2337 */
2338
2339 return tle->ressortgroupref;
2340 }
2341
2342 /*
2343 * Transform a list of expressions within a GROUP BY clause or grouping set.
2344 *
2345 * The list of expressions belongs to a single clause within which duplicates
2346 * can be safely eliminated.
2347 *
2348 * Returns an integer list of ressortgroupref values.
2349 *
2350 * flatresult reference to flat list of SortGroupClause nodes
2351 * pstate ParseState
2352 * list nodes to transform
2353 * targetlist reference to TargetEntry list
2354 * sortClause ORDER BY clause (SortGroupClause nodes)
2355 * exprKind expression kind
2356 * useSQL99 SQL99 rather than SQL92 syntax
2357 * toplevel false if within any grouping set
2358 */
2359 static List *
transformGroupClauseList(List ** flatresult,ParseState * pstate,List * list,List ** targetlist,List * sortClause,ParseExprKind exprKind,bool useSQL99,bool toplevel)2360 transformGroupClauseList(List **flatresult,
2361 ParseState *pstate, List *list,
2362 List **targetlist, List *sortClause,
2363 ParseExprKind exprKind, bool useSQL99, bool toplevel)
2364 {
2365 Bitmapset *seen_local = NULL;
2366 List *result = NIL;
2367 ListCell *gl;
2368
2369 foreach(gl, list)
2370 {
2371 Node *gexpr = (Node *) lfirst(gl);
2372
2373 Index ref = transformGroupClauseExpr(flatresult,
2374 seen_local,
2375 pstate,
2376 gexpr,
2377 targetlist,
2378 sortClause,
2379 exprKind,
2380 useSQL99,
2381 toplevel);
2382
2383 if (ref > 0)
2384 {
2385 seen_local = bms_add_member(seen_local, ref);
2386 result = lappend_int(result, ref);
2387 }
2388 }
2389
2390 return result;
2391 }
2392
2393 /*
2394 * Transform a grouping set and (recursively) its content.
2395 *
2396 * The grouping set might be a GROUPING SETS node with other grouping sets
2397 * inside it, but SETS within SETS have already been flattened out before
2398 * reaching here.
2399 *
2400 * Returns the transformed node, which now contains SIMPLE nodes with lists
2401 * of ressortgrouprefs rather than expressions.
2402 *
2403 * flatresult reference to flat list of SortGroupClause nodes
2404 * pstate ParseState
2405 * gset grouping set to transform
2406 * targetlist reference to TargetEntry list
2407 * sortClause ORDER BY clause (SortGroupClause nodes)
2408 * exprKind expression kind
2409 * useSQL99 SQL99 rather than SQL92 syntax
2410 * toplevel false if within any grouping set
2411 */
2412 static Node *
transformGroupingSet(List ** flatresult,ParseState * pstate,GroupingSet * gset,List ** targetlist,List * sortClause,ParseExprKind exprKind,bool useSQL99,bool toplevel)2413 transformGroupingSet(List **flatresult,
2414 ParseState *pstate, GroupingSet *gset,
2415 List **targetlist, List *sortClause,
2416 ParseExprKind exprKind, bool useSQL99, bool toplevel)
2417 {
2418 ListCell *gl;
2419 List *content = NIL;
2420
2421 Assert(toplevel || gset->kind != GROUPING_SET_SETS);
2422
2423 foreach(gl, gset->content)
2424 {
2425 Node *n = lfirst(gl);
2426
2427 if (IsA(n, List))
2428 {
2429 List *l = transformGroupClauseList(flatresult,
2430 pstate, (List *) n,
2431 targetlist, sortClause,
2432 exprKind, useSQL99, false);
2433
2434 content = lappend(content, makeGroupingSet(GROUPING_SET_SIMPLE,
2435 l,
2436 exprLocation(n)));
2437 }
2438 else if (IsA(n, GroupingSet))
2439 {
2440 GroupingSet *gset2 = (GroupingSet *) lfirst(gl);
2441
2442 content = lappend(content, transformGroupingSet(flatresult,
2443 pstate, gset2,
2444 targetlist, sortClause,
2445 exprKind, useSQL99, false));
2446 }
2447 else
2448 {
2449 Index ref = transformGroupClauseExpr(flatresult,
2450 NULL,
2451 pstate,
2452 n,
2453 targetlist,
2454 sortClause,
2455 exprKind,
2456 useSQL99,
2457 false);
2458
2459 content = lappend(content, makeGroupingSet(GROUPING_SET_SIMPLE,
2460 list_make1_int(ref),
2461 exprLocation(n)));
2462 }
2463 }
2464
2465 /* Arbitrarily cap the size of CUBE, which has exponential growth */
2466 if (gset->kind == GROUPING_SET_CUBE)
2467 {
2468 if (list_length(content) > 12)
2469 ereport(ERROR,
2470 (errcode(ERRCODE_TOO_MANY_COLUMNS),
2471 errmsg("CUBE is limited to 12 elements"),
2472 parser_errposition(pstate, gset->location)));
2473 }
2474
2475 return (Node *) makeGroupingSet(gset->kind, content, gset->location);
2476 }
2477
2478
2479 /*
2480 * transformGroupClause -
2481 * transform a GROUP BY clause
2482 *
2483 * GROUP BY items will be added to the targetlist (as resjunk columns)
2484 * if not already present, so the targetlist must be passed by reference.
2485 *
2486 * This is also used for window PARTITION BY clauses (which act almost the
2487 * same, but are always interpreted per SQL99 rules).
2488 *
2489 * Grouping sets make this a lot more complex than it was. Our goal here is
2490 * twofold: we make a flat list of SortGroupClause nodes referencing each
2491 * distinct expression used for grouping, with those expressions added to the
2492 * targetlist if needed. At the same time, we build the groupingSets tree,
2493 * which stores only ressortgrouprefs as integer lists inside GroupingSet nodes
2494 * (possibly nested, but limited in depth: a GROUPING_SET_SETS node can contain
2495 * nested SIMPLE, CUBE or ROLLUP nodes, but not more sets - we flatten that
2496 * out; while CUBE and ROLLUP can contain only SIMPLE nodes).
2497 *
2498 * We skip much of the hard work if there are no grouping sets.
2499 *
2500 * One subtlety is that the groupClause list can end up empty while the
2501 * groupingSets list is not; this happens if there are only empty grouping
2502 * sets, or an explicit GROUP BY (). This has the same effect as specifying
2503 * aggregates or a HAVING clause with no GROUP BY; the output is one row per
2504 * grouping set even if the input is empty.
2505 *
2506 * Returns the transformed (flat) groupClause.
2507 *
2508 * pstate ParseState
2509 * grouplist clause to transform
2510 * groupingSets reference to list to contain the grouping set tree
2511 * targetlist reference to TargetEntry list
2512 * sortClause ORDER BY clause (SortGroupClause nodes)
2513 * exprKind expression kind
2514 * useSQL99 SQL99 rather than SQL92 syntax
2515 */
2516 List *
transformGroupClause(ParseState * pstate,List * grouplist,List ** groupingSets,List ** targetlist,List * sortClause,ParseExprKind exprKind,bool useSQL99)2517 transformGroupClause(ParseState *pstate, List *grouplist, List **groupingSets,
2518 List **targetlist, List *sortClause,
2519 ParseExprKind exprKind, bool useSQL99)
2520 {
2521 List *result = NIL;
2522 List *flat_grouplist;
2523 List *gsets = NIL;
2524 ListCell *gl;
2525 bool hasGroupingSets = false;
2526 Bitmapset *seen_local = NULL;
2527
2528 /*
2529 * Recursively flatten implicit RowExprs. (Technically this is only needed
2530 * for GROUP BY, per the syntax rules for grouping sets, but we do it
2531 * anyway.)
2532 */
2533 flat_grouplist = (List *) flatten_grouping_sets((Node *) grouplist,
2534 true,
2535 &hasGroupingSets);
2536
2537 /*
2538 * If the list is now empty, but hasGroupingSets is true, it's because we
2539 * elided redundant empty grouping sets. Restore a single empty grouping
2540 * set to leave a canonical form: GROUP BY ()
2541 */
2542
2543 if (flat_grouplist == NIL && hasGroupingSets)
2544 {
2545 flat_grouplist = list_make1(makeGroupingSet(GROUPING_SET_EMPTY,
2546 NIL,
2547 exprLocation((Node *) grouplist)));
2548 }
2549
2550 foreach(gl, flat_grouplist)
2551 {
2552 Node *gexpr = (Node *) lfirst(gl);
2553
2554 if (IsA(gexpr, GroupingSet))
2555 {
2556 GroupingSet *gset = (GroupingSet *) gexpr;
2557
2558 switch (gset->kind)
2559 {
2560 case GROUPING_SET_EMPTY:
2561 gsets = lappend(gsets, gset);
2562 break;
2563 case GROUPING_SET_SIMPLE:
2564 /* can't happen */
2565 Assert(false);
2566 break;
2567 case GROUPING_SET_SETS:
2568 case GROUPING_SET_CUBE:
2569 case GROUPING_SET_ROLLUP:
2570 gsets = lappend(gsets,
2571 transformGroupingSet(&result,
2572 pstate, gset,
2573 targetlist, sortClause,
2574 exprKind, useSQL99, true));
2575 break;
2576 }
2577 }
2578 else
2579 {
2580 Index ref = transformGroupClauseExpr(&result, seen_local,
2581 pstate, gexpr,
2582 targetlist, sortClause,
2583 exprKind, useSQL99, true);
2584
2585 if (ref > 0)
2586 {
2587 seen_local = bms_add_member(seen_local, ref);
2588 if (hasGroupingSets)
2589 gsets = lappend(gsets,
2590 makeGroupingSet(GROUPING_SET_SIMPLE,
2591 list_make1_int(ref),
2592 exprLocation(gexpr)));
2593 }
2594 }
2595 }
2596
2597 /* parser should prevent this */
2598 Assert(gsets == NIL || groupingSets != NULL);
2599
2600 if (groupingSets)
2601 *groupingSets = gsets;
2602
2603 return result;
2604 }
2605
2606 /*
2607 * transformSortClause -
2608 * transform an ORDER BY clause
2609 *
2610 * ORDER BY items will be added to the targetlist (as resjunk columns)
2611 * if not already present, so the targetlist must be passed by reference.
2612 *
2613 * This is also used for window and aggregate ORDER BY clauses (which act
2614 * almost the same, but are always interpreted per SQL99 rules).
2615 */
2616 List *
transformSortClause(ParseState * pstate,List * orderlist,List ** targetlist,ParseExprKind exprKind,bool useSQL99)2617 transformSortClause(ParseState *pstate,
2618 List *orderlist,
2619 List **targetlist,
2620 ParseExprKind exprKind,
2621 bool useSQL99)
2622 {
2623 List *sortlist = NIL;
2624 ListCell *olitem;
2625
2626 foreach(olitem, orderlist)
2627 {
2628 SortBy *sortby = (SortBy *) lfirst(olitem);
2629 TargetEntry *tle;
2630
2631 if (useSQL99)
2632 tle = findTargetlistEntrySQL99(pstate, sortby->node,
2633 targetlist, exprKind);
2634 else
2635 tle = findTargetlistEntrySQL92(pstate, sortby->node,
2636 targetlist, exprKind);
2637
2638 sortlist = addTargetToSortList(pstate, tle,
2639 sortlist, *targetlist, sortby);
2640 }
2641
2642 return sortlist;
2643 }
2644
2645 /*
2646 * transformWindowDefinitions -
2647 * transform window definitions (WindowDef to WindowClause)
2648 */
2649 List *
transformWindowDefinitions(ParseState * pstate,List * windowdefs,List ** targetlist)2650 transformWindowDefinitions(ParseState *pstate,
2651 List *windowdefs,
2652 List **targetlist)
2653 {
2654 List *result = NIL;
2655 Index winref = 0;
2656 ListCell *lc;
2657
2658 foreach(lc, windowdefs)
2659 {
2660 WindowDef *windef = (WindowDef *) lfirst(lc);
2661 WindowClause *refwc = NULL;
2662 List *partitionClause;
2663 List *orderClause;
2664 Oid rangeopfamily = InvalidOid;
2665 Oid rangeopcintype = InvalidOid;
2666 WindowClause *wc;
2667
2668 winref++;
2669
2670 /*
2671 * Check for duplicate window names.
2672 */
2673 if (windef->name &&
2674 findWindowClause(result, windef->name) != NULL)
2675 ereport(ERROR,
2676 (errcode(ERRCODE_WINDOWING_ERROR),
2677 errmsg("window \"%s\" is already defined", windef->name),
2678 parser_errposition(pstate, windef->location)));
2679
2680 /*
2681 * If it references a previous window, look that up.
2682 */
2683 if (windef->refname)
2684 {
2685 refwc = findWindowClause(result, windef->refname);
2686 if (refwc == NULL)
2687 ereport(ERROR,
2688 (errcode(ERRCODE_UNDEFINED_OBJECT),
2689 errmsg("window \"%s\" does not exist",
2690 windef->refname),
2691 parser_errposition(pstate, windef->location)));
2692 }
2693
2694 /*
2695 * Transform PARTITION and ORDER specs, if any. These are treated
2696 * almost exactly like top-level GROUP BY and ORDER BY clauses,
2697 * including the special handling of nondefault operator semantics.
2698 */
2699 orderClause = transformSortClause(pstate,
2700 windef->orderClause,
2701 targetlist,
2702 EXPR_KIND_WINDOW_ORDER,
2703 true /* force SQL99 rules */ );
2704 partitionClause = transformGroupClause(pstate,
2705 windef->partitionClause,
2706 NULL,
2707 targetlist,
2708 orderClause,
2709 EXPR_KIND_WINDOW_PARTITION,
2710 true /* force SQL99 rules */ );
2711
2712 /*
2713 * And prepare the new WindowClause.
2714 */
2715 wc = makeNode(WindowClause);
2716 wc->name = windef->name;
2717 wc->refname = windef->refname;
2718
2719 /*
2720 * Per spec, a windowdef that references a previous one copies the
2721 * previous partition clause (and mustn't specify its own). It can
2722 * specify its own ordering clause, but only if the previous one had
2723 * none. It always specifies its own frame clause, and the previous
2724 * one must not have a frame clause. Yeah, it's bizarre that each of
2725 * these cases works differently, but SQL:2008 says so; see 7.11
2726 * <window clause> syntax rule 10 and general rule 1. The frame
2727 * clause rule is especially bizarre because it makes "OVER foo"
2728 * different from "OVER (foo)", and requires the latter to throw an
2729 * error if foo has a nondefault frame clause. Well, ours not to
2730 * reason why, but we do go out of our way to throw a useful error
2731 * message for such cases.
2732 */
2733 if (refwc)
2734 {
2735 if (partitionClause)
2736 ereport(ERROR,
2737 (errcode(ERRCODE_WINDOWING_ERROR),
2738 errmsg("cannot override PARTITION BY clause of window \"%s\"",
2739 windef->refname),
2740 parser_errposition(pstate, windef->location)));
2741 wc->partitionClause = copyObject(refwc->partitionClause);
2742 }
2743 else
2744 wc->partitionClause = partitionClause;
2745 if (refwc)
2746 {
2747 if (orderClause && refwc->orderClause)
2748 ereport(ERROR,
2749 (errcode(ERRCODE_WINDOWING_ERROR),
2750 errmsg("cannot override ORDER BY clause of window \"%s\"",
2751 windef->refname),
2752 parser_errposition(pstate, windef->location)));
2753 if (orderClause)
2754 {
2755 wc->orderClause = orderClause;
2756 wc->copiedOrder = false;
2757 }
2758 else
2759 {
2760 wc->orderClause = copyObject(refwc->orderClause);
2761 wc->copiedOrder = true;
2762 }
2763 }
2764 else
2765 {
2766 wc->orderClause = orderClause;
2767 wc->copiedOrder = false;
2768 }
2769 if (refwc && refwc->frameOptions != FRAMEOPTION_DEFAULTS)
2770 {
2771 /*
2772 * Use this message if this is a WINDOW clause, or if it's an OVER
2773 * clause that includes ORDER BY or framing clauses. (We already
2774 * rejected PARTITION BY above, so no need to check that.)
2775 */
2776 if (windef->name ||
2777 orderClause || windef->frameOptions != FRAMEOPTION_DEFAULTS)
2778 ereport(ERROR,
2779 (errcode(ERRCODE_WINDOWING_ERROR),
2780 errmsg("cannot copy window \"%s\" because it has a frame clause",
2781 windef->refname),
2782 parser_errposition(pstate, windef->location)));
2783 /* Else this clause is just OVER (foo), so say this: */
2784 ereport(ERROR,
2785 (errcode(ERRCODE_WINDOWING_ERROR),
2786 errmsg("cannot copy window \"%s\" because it has a frame clause",
2787 windef->refname),
2788 errhint("Omit the parentheses in this OVER clause."),
2789 parser_errposition(pstate, windef->location)));
2790 }
2791 wc->frameOptions = windef->frameOptions;
2792
2793 /*
2794 * RANGE offset PRECEDING/FOLLOWING requires exactly one ORDER BY
2795 * column; check that and get its sort opfamily info.
2796 */
2797 if ((wc->frameOptions & FRAMEOPTION_RANGE) &&
2798 (wc->frameOptions & (FRAMEOPTION_START_OFFSET |
2799 FRAMEOPTION_END_OFFSET)))
2800 {
2801 SortGroupClause *sortcl;
2802 Node *sortkey;
2803 int16 rangestrategy;
2804
2805 if (list_length(wc->orderClause) != 1)
2806 ereport(ERROR,
2807 (errcode(ERRCODE_WINDOWING_ERROR),
2808 errmsg("RANGE with offset PRECEDING/FOLLOWING requires exactly one ORDER BY column"),
2809 parser_errposition(pstate, windef->location)));
2810 sortcl = castNode(SortGroupClause, linitial(wc->orderClause));
2811 sortkey = get_sortgroupclause_expr(sortcl, *targetlist);
2812 /* Find the sort operator in pg_amop */
2813 if (!get_ordering_op_properties(sortcl->sortop,
2814 &rangeopfamily,
2815 &rangeopcintype,
2816 &rangestrategy))
2817 elog(ERROR, "operator %u is not a valid ordering operator",
2818 sortcl->sortop);
2819 /* Record properties of sort ordering */
2820 wc->inRangeColl = exprCollation(sortkey);
2821 wc->inRangeAsc = (rangestrategy == BTLessStrategyNumber);
2822 wc->inRangeNullsFirst = sortcl->nulls_first;
2823 }
2824
2825 /* Per spec, GROUPS mode requires an ORDER BY clause */
2826 if (wc->frameOptions & FRAMEOPTION_GROUPS)
2827 {
2828 if (wc->orderClause == NIL)
2829 ereport(ERROR,
2830 (errcode(ERRCODE_WINDOWING_ERROR),
2831 errmsg("GROUPS mode requires an ORDER BY clause"),
2832 parser_errposition(pstate, windef->location)));
2833 }
2834
2835 /* Process frame offset expressions */
2836 wc->startOffset = transformFrameOffset(pstate, wc->frameOptions,
2837 rangeopfamily, rangeopcintype,
2838 &wc->startInRangeFunc,
2839 windef->startOffset);
2840 wc->endOffset = transformFrameOffset(pstate, wc->frameOptions,
2841 rangeopfamily, rangeopcintype,
2842 &wc->endInRangeFunc,
2843 windef->endOffset);
2844 wc->winref = winref;
2845
2846 result = lappend(result, wc);
2847 }
2848
2849 return result;
2850 }
2851
2852 /*
2853 * transformDistinctClause -
2854 * transform a DISTINCT clause
2855 *
2856 * Since we may need to add items to the query's targetlist, that list
2857 * is passed by reference.
2858 *
2859 * As with GROUP BY, we absorb the sorting semantics of ORDER BY as much as
2860 * possible into the distinctClause. This avoids a possible need to re-sort,
2861 * and allows the user to choose the equality semantics used by DISTINCT,
2862 * should she be working with a datatype that has more than one equality
2863 * operator.
2864 *
2865 * is_agg is true if we are transforming an aggregate(DISTINCT ...)
2866 * function call. This does not affect any behavior, only the phrasing
2867 * of error messages.
2868 */
2869 List *
transformDistinctClause(ParseState * pstate,List ** targetlist,List * sortClause,bool is_agg)2870 transformDistinctClause(ParseState *pstate,
2871 List **targetlist, List *sortClause, bool is_agg)
2872 {
2873 List *result = NIL;
2874 ListCell *slitem;
2875 ListCell *tlitem;
2876
2877 /*
2878 * The distinctClause should consist of all ORDER BY items followed by all
2879 * other non-resjunk targetlist items. There must not be any resjunk
2880 * ORDER BY items --- that would imply that we are sorting by a value that
2881 * isn't necessarily unique within a DISTINCT group, so the results
2882 * wouldn't be well-defined. This construction ensures we follow the rule
2883 * that sortClause and distinctClause match; in fact the sortClause will
2884 * always be a prefix of distinctClause.
2885 *
2886 * Note a corner case: the same TLE could be in the ORDER BY list multiple
2887 * times with different sortops. We have to include it in the
2888 * distinctClause the same way to preserve the prefix property. The net
2889 * effect will be that the TLE value will be made unique according to both
2890 * sortops.
2891 */
2892 foreach(slitem, sortClause)
2893 {
2894 SortGroupClause *scl = (SortGroupClause *) lfirst(slitem);
2895 TargetEntry *tle = get_sortgroupclause_tle(scl, *targetlist);
2896
2897 if (tle->resjunk)
2898 ereport(ERROR,
2899 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
2900 is_agg ?
2901 errmsg("in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list") :
2902 errmsg("for SELECT DISTINCT, ORDER BY expressions must appear in select list"),
2903 parser_errposition(pstate,
2904 exprLocation((Node *) tle->expr))));
2905 result = lappend(result, copyObject(scl));
2906 }
2907
2908 /*
2909 * Now add any remaining non-resjunk tlist items, using default sort/group
2910 * semantics for their data types.
2911 */
2912 foreach(tlitem, *targetlist)
2913 {
2914 TargetEntry *tle = (TargetEntry *) lfirst(tlitem);
2915
2916 if (tle->resjunk)
2917 continue; /* ignore junk */
2918 result = addTargetToGroupList(pstate, tle,
2919 result, *targetlist,
2920 exprLocation((Node *) tle->expr));
2921 }
2922
2923 /*
2924 * Complain if we found nothing to make DISTINCT. Returning an empty list
2925 * would cause the parsed Query to look like it didn't have DISTINCT, with
2926 * results that would probably surprise the user. Note: this case is
2927 * presently impossible for aggregates because of grammar restrictions,
2928 * but we check anyway.
2929 */
2930 if (result == NIL)
2931 ereport(ERROR,
2932 (errcode(ERRCODE_SYNTAX_ERROR),
2933 is_agg ?
2934 errmsg("an aggregate with DISTINCT must have at least one argument") :
2935 errmsg("SELECT DISTINCT must have at least one column")));
2936
2937 return result;
2938 }
2939
2940 /*
2941 * transformDistinctOnClause -
2942 * transform a DISTINCT ON clause
2943 *
2944 * Since we may need to add items to the query's targetlist, that list
2945 * is passed by reference.
2946 *
2947 * As with GROUP BY, we absorb the sorting semantics of ORDER BY as much as
2948 * possible into the distinctClause. This avoids a possible need to re-sort,
2949 * and allows the user to choose the equality semantics used by DISTINCT,
2950 * should she be working with a datatype that has more than one equality
2951 * operator.
2952 */
2953 List *
transformDistinctOnClause(ParseState * pstate,List * distinctlist,List ** targetlist,List * sortClause)2954 transformDistinctOnClause(ParseState *pstate, List *distinctlist,
2955 List **targetlist, List *sortClause)
2956 {
2957 List *result = NIL;
2958 List *sortgrouprefs = NIL;
2959 bool skipped_sortitem;
2960 ListCell *lc;
2961 ListCell *lc2;
2962
2963 /*
2964 * Add all the DISTINCT ON expressions to the tlist (if not already
2965 * present, they are added as resjunk items). Assign sortgroupref numbers
2966 * to them, and make a list of these numbers. (NB: we rely below on the
2967 * sortgrouprefs list being one-for-one with the original distinctlist.
2968 * Also notice that we could have duplicate DISTINCT ON expressions and
2969 * hence duplicate entries in sortgrouprefs.)
2970 */
2971 foreach(lc, distinctlist)
2972 {
2973 Node *dexpr = (Node *) lfirst(lc);
2974 int sortgroupref;
2975 TargetEntry *tle;
2976
2977 tle = findTargetlistEntrySQL92(pstate, dexpr, targetlist,
2978 EXPR_KIND_DISTINCT_ON);
2979 sortgroupref = assignSortGroupRef(tle, *targetlist);
2980 sortgrouprefs = lappend_int(sortgrouprefs, sortgroupref);
2981 }
2982
2983 /*
2984 * If the user writes both DISTINCT ON and ORDER BY, adopt the sorting
2985 * semantics from ORDER BY items that match DISTINCT ON items, and also
2986 * adopt their column sort order. We insist that the distinctClause and
2987 * sortClause match, so throw error if we find the need to add any more
2988 * distinctClause items after we've skipped an ORDER BY item that wasn't
2989 * in DISTINCT ON.
2990 */
2991 skipped_sortitem = false;
2992 foreach(lc, sortClause)
2993 {
2994 SortGroupClause *scl = (SortGroupClause *) lfirst(lc);
2995
2996 if (list_member_int(sortgrouprefs, scl->tleSortGroupRef))
2997 {
2998 if (skipped_sortitem)
2999 ereport(ERROR,
3000 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
3001 errmsg("SELECT DISTINCT ON expressions must match initial ORDER BY expressions"),
3002 parser_errposition(pstate,
3003 get_matching_location(scl->tleSortGroupRef,
3004 sortgrouprefs,
3005 distinctlist))));
3006 else
3007 result = lappend(result, copyObject(scl));
3008 }
3009 else
3010 skipped_sortitem = true;
3011 }
3012
3013 /*
3014 * Now add any remaining DISTINCT ON items, using default sort/group
3015 * semantics for their data types. (Note: this is pretty questionable; if
3016 * the ORDER BY list doesn't include all the DISTINCT ON items and more
3017 * besides, you certainly aren't using DISTINCT ON in the intended way,
3018 * and you probably aren't going to get consistent results. It might be
3019 * better to throw an error or warning here. But historically we've
3020 * allowed it, so keep doing so.)
3021 */
3022 forboth(lc, distinctlist, lc2, sortgrouprefs)
3023 {
3024 Node *dexpr = (Node *) lfirst(lc);
3025 int sortgroupref = lfirst_int(lc2);
3026 TargetEntry *tle = get_sortgroupref_tle(sortgroupref, *targetlist);
3027
3028 if (targetIsInSortList(tle, InvalidOid, result))
3029 continue; /* already in list (with some semantics) */
3030 if (skipped_sortitem)
3031 ereport(ERROR,
3032 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
3033 errmsg("SELECT DISTINCT ON expressions must match initial ORDER BY expressions"),
3034 parser_errposition(pstate, exprLocation(dexpr))));
3035 result = addTargetToGroupList(pstate, tle,
3036 result, *targetlist,
3037 exprLocation(dexpr));
3038 }
3039
3040 /*
3041 * An empty result list is impossible here because of grammar
3042 * restrictions.
3043 */
3044 Assert(result != NIL);
3045
3046 return result;
3047 }
3048
3049 /*
3050 * get_matching_location
3051 * Get the exprLocation of the exprs member corresponding to the
3052 * (first) member of sortgrouprefs that equals sortgroupref.
3053 *
3054 * This is used so that we can point at a troublesome DISTINCT ON entry.
3055 * (Note that we need to use the original untransformed DISTINCT ON list
3056 * item, as whatever TLE it corresponds to will very possibly have a
3057 * parse location pointing to some matching entry in the SELECT list
3058 * or ORDER BY list.)
3059 */
3060 static int
get_matching_location(int sortgroupref,List * sortgrouprefs,List * exprs)3061 get_matching_location(int sortgroupref, List *sortgrouprefs, List *exprs)
3062 {
3063 ListCell *lcs;
3064 ListCell *lce;
3065
3066 forboth(lcs, sortgrouprefs, lce, exprs)
3067 {
3068 if (lfirst_int(lcs) == sortgroupref)
3069 return exprLocation((Node *) lfirst(lce));
3070 }
3071 /* if no match, caller blew it */
3072 elog(ERROR, "get_matching_location: no matching sortgroupref");
3073 return -1; /* keep compiler quiet */
3074 }
3075
3076 /*
3077 * resolve_unique_index_expr
3078 * Infer a unique index from a list of indexElems, for ON
3079 * CONFLICT clause
3080 *
3081 * Perform parse analysis of expressions and columns appearing within ON
3082 * CONFLICT clause. During planning, the returned list of expressions is used
3083 * to infer which unique index to use.
3084 */
3085 static List *
resolve_unique_index_expr(ParseState * pstate,InferClause * infer,Relation heapRel)3086 resolve_unique_index_expr(ParseState *pstate, InferClause *infer,
3087 Relation heapRel)
3088 {
3089 List *result = NIL;
3090 ListCell *l;
3091
3092 foreach(l, infer->indexElems)
3093 {
3094 IndexElem *ielem = (IndexElem *) lfirst(l);
3095 InferenceElem *pInfer = makeNode(InferenceElem);
3096 Node *parse;
3097
3098 /*
3099 * Raw grammar re-uses CREATE INDEX infrastructure for unique index
3100 * inference clause, and so will accept opclasses by name and so on.
3101 *
3102 * Make no attempt to match ASC or DESC ordering or NULLS FIRST/NULLS
3103 * LAST ordering, since those are not significant for inference
3104 * purposes (any unique index matching the inference specification in
3105 * other regards is accepted indifferently). Actively reject this as
3106 * wrong-headed.
3107 */
3108 if (ielem->ordering != SORTBY_DEFAULT)
3109 ereport(ERROR,
3110 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
3111 errmsg("ASC/DESC is not allowed in ON CONFLICT clause"),
3112 parser_errposition(pstate,
3113 exprLocation((Node *) infer))));
3114 if (ielem->nulls_ordering != SORTBY_NULLS_DEFAULT)
3115 ereport(ERROR,
3116 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
3117 errmsg("NULLS FIRST/LAST is not allowed in ON CONFLICT clause"),
3118 parser_errposition(pstate,
3119 exprLocation((Node *) infer))));
3120
3121 if (!ielem->expr)
3122 {
3123 /* Simple index attribute */
3124 ColumnRef *n;
3125
3126 /*
3127 * Grammar won't have built raw expression for us in event of
3128 * plain column reference. Create one directly, and perform
3129 * expression transformation. Planner expects this, and performs
3130 * its own normalization for the purposes of matching against
3131 * pg_index.
3132 */
3133 n = makeNode(ColumnRef);
3134 n->fields = list_make1(makeString(ielem->name));
3135 /* Location is approximately that of inference specification */
3136 n->location = infer->location;
3137 parse = (Node *) n;
3138 }
3139 else
3140 {
3141 /* Do parse transformation of the raw expression */
3142 parse = (Node *) ielem->expr;
3143 }
3144
3145 /*
3146 * transformExpr() will reject subqueries, aggregates, window
3147 * functions, and SRFs, based on being passed
3148 * EXPR_KIND_INDEX_EXPRESSION. So we needn't worry about those
3149 * further ... not that they would match any available index
3150 * expression anyway.
3151 */
3152 pInfer->expr = transformExpr(pstate, parse, EXPR_KIND_INDEX_EXPRESSION);
3153
3154 /* Perform lookup of collation and operator class as required */
3155 if (!ielem->collation)
3156 pInfer->infercollid = InvalidOid;
3157 else
3158 pInfer->infercollid = LookupCollation(pstate, ielem->collation,
3159 exprLocation(pInfer->expr));
3160
3161 if (!ielem->opclass)
3162 pInfer->inferopclass = InvalidOid;
3163 else
3164 pInfer->inferopclass = get_opclass_oid(BTREE_AM_OID,
3165 ielem->opclass, false);
3166
3167 result = lappend(result, pInfer);
3168 }
3169
3170 return result;
3171 }
3172
3173 /*
3174 * transformOnConflictArbiter -
3175 * transform arbiter expressions in an ON CONFLICT clause.
3176 *
3177 * Transformed expressions used to infer one unique index relation to serve as
3178 * an ON CONFLICT arbiter. Partial unique indexes may be inferred using WHERE
3179 * clause from inference specification clause.
3180 */
3181 void
transformOnConflictArbiter(ParseState * pstate,OnConflictClause * onConflictClause,List ** arbiterExpr,Node ** arbiterWhere,Oid * constraint)3182 transformOnConflictArbiter(ParseState *pstate,
3183 OnConflictClause *onConflictClause,
3184 List **arbiterExpr, Node **arbiterWhere,
3185 Oid *constraint)
3186 {
3187 InferClause *infer = onConflictClause->infer;
3188
3189 *arbiterExpr = NIL;
3190 *arbiterWhere = NULL;
3191 *constraint = InvalidOid;
3192
3193 if (onConflictClause->action == ONCONFLICT_UPDATE && !infer)
3194 ereport(ERROR,
3195 (errcode(ERRCODE_SYNTAX_ERROR),
3196 errmsg("ON CONFLICT DO UPDATE requires inference specification or constraint name"),
3197 errhint("For example, ON CONFLICT (column_name)."),
3198 parser_errposition(pstate,
3199 exprLocation((Node *) onConflictClause))));
3200
3201 /*
3202 * To simplify certain aspects of its design, speculative insertion into
3203 * system catalogs is disallowed
3204 */
3205 if (IsCatalogRelation(pstate->p_target_relation))
3206 ereport(ERROR,
3207 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3208 errmsg("ON CONFLICT is not supported with system catalog tables"),
3209 parser_errposition(pstate,
3210 exprLocation((Node *) onConflictClause))));
3211
3212 /* Same applies to table used by logical decoding as catalog table */
3213 if (RelationIsUsedAsCatalogTable(pstate->p_target_relation))
3214 ereport(ERROR,
3215 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3216 errmsg("ON CONFLICT is not supported on table \"%s\" used as a catalog table",
3217 RelationGetRelationName(pstate->p_target_relation)),
3218 parser_errposition(pstate,
3219 exprLocation((Node *) onConflictClause))));
3220
3221 /* ON CONFLICT DO NOTHING does not require an inference clause */
3222 if (infer)
3223 {
3224 if (infer->indexElems)
3225 *arbiterExpr = resolve_unique_index_expr(pstate, infer,
3226 pstate->p_target_relation);
3227
3228 /*
3229 * Handling inference WHERE clause (for partial unique index
3230 * inference)
3231 */
3232 if (infer->whereClause)
3233 *arbiterWhere = transformExpr(pstate, infer->whereClause,
3234 EXPR_KIND_INDEX_PREDICATE);
3235
3236 /*
3237 * If the arbiter is specified by constraint name, get the constraint
3238 * OID and mark the constrained columns as requiring SELECT privilege,
3239 * in the same way as would have happened if the arbiter had been
3240 * specified by explicit reference to the constraint's index columns.
3241 */
3242 if (infer->conname)
3243 {
3244 Oid relid = RelationGetRelid(pstate->p_target_relation);
3245 RangeTblEntry *rte = pstate->p_target_nsitem->p_rte;
3246 Bitmapset *conattnos;
3247
3248 conattnos = get_relation_constraint_attnos(relid, infer->conname,
3249 false, constraint);
3250
3251 /* Make sure the rel as a whole is marked for SELECT access */
3252 rte->requiredPerms |= ACL_SELECT;
3253 /* Mark the constrained columns as requiring SELECT access */
3254 rte->selectedCols = bms_add_members(rte->selectedCols, conattnos);
3255 }
3256 }
3257
3258 /*
3259 * It's convenient to form a list of expressions based on the
3260 * representation used by CREATE INDEX, since the same restrictions are
3261 * appropriate (e.g. on subqueries). However, from here on, a dedicated
3262 * primnode representation is used for inference elements, and so
3263 * assign_query_collations() can be trusted to do the right thing with the
3264 * post parse analysis query tree inference clause representation.
3265 */
3266 }
3267
3268 /*
3269 * addTargetToSortList
3270 * If the given targetlist entry isn't already in the SortGroupClause
3271 * list, add it to the end of the list, using the given sort ordering
3272 * info.
3273 *
3274 * Returns the updated SortGroupClause list.
3275 */
3276 List *
addTargetToSortList(ParseState * pstate,TargetEntry * tle,List * sortlist,List * targetlist,SortBy * sortby)3277 addTargetToSortList(ParseState *pstate, TargetEntry *tle,
3278 List *sortlist, List *targetlist, SortBy *sortby)
3279 {
3280 Oid restype = exprType((Node *) tle->expr);
3281 Oid sortop;
3282 Oid eqop;
3283 bool hashable;
3284 bool reverse;
3285 int location;
3286 ParseCallbackState pcbstate;
3287
3288 /* if tlist item is an UNKNOWN literal, change it to TEXT */
3289 if (restype == UNKNOWNOID)
3290 {
3291 tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
3292 restype, TEXTOID, -1,
3293 COERCION_IMPLICIT,
3294 COERCE_IMPLICIT_CAST,
3295 -1);
3296 restype = TEXTOID;
3297 }
3298
3299 /*
3300 * Rather than clutter the API of get_sort_group_operators and the other
3301 * functions we're about to use, make use of error context callback to
3302 * mark any error reports with a parse position. We point to the operator
3303 * location if present, else to the expression being sorted. (NB: use the
3304 * original untransformed expression here; the TLE entry might well point
3305 * at a duplicate expression in the regular SELECT list.)
3306 */
3307 location = sortby->location;
3308 if (location < 0)
3309 location = exprLocation(sortby->node);
3310 setup_parser_errposition_callback(&pcbstate, pstate, location);
3311
3312 /* determine the sortop, eqop, and directionality */
3313 switch (sortby->sortby_dir)
3314 {
3315 case SORTBY_DEFAULT:
3316 case SORTBY_ASC:
3317 get_sort_group_operators(restype,
3318 true, true, false,
3319 &sortop, &eqop, NULL,
3320 &hashable);
3321 reverse = false;
3322 break;
3323 case SORTBY_DESC:
3324 get_sort_group_operators(restype,
3325 false, true, true,
3326 NULL, &eqop, &sortop,
3327 &hashable);
3328 reverse = true;
3329 break;
3330 case SORTBY_USING:
3331 Assert(sortby->useOp != NIL);
3332 sortop = compatible_oper_opid(sortby->useOp,
3333 restype,
3334 restype,
3335 false);
3336
3337 /*
3338 * Verify it's a valid ordering operator, fetch the corresponding
3339 * equality operator, and determine whether to consider it like
3340 * ASC or DESC.
3341 */
3342 eqop = get_equality_op_for_ordering_op(sortop, &reverse);
3343 if (!OidIsValid(eqop))
3344 ereport(ERROR,
3345 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3346 errmsg("operator %s is not a valid ordering operator",
3347 strVal(llast(sortby->useOp))),
3348 errhint("Ordering operators must be \"<\" or \">\" members of btree operator families.")));
3349
3350 /*
3351 * Also see if the equality operator is hashable.
3352 */
3353 hashable = op_hashjoinable(eqop, restype);
3354 break;
3355 default:
3356 elog(ERROR, "unrecognized sortby_dir: %d", sortby->sortby_dir);
3357 sortop = InvalidOid; /* keep compiler quiet */
3358 eqop = InvalidOid;
3359 hashable = false;
3360 reverse = false;
3361 break;
3362 }
3363
3364 cancel_parser_errposition_callback(&pcbstate);
3365
3366 /* avoid making duplicate sortlist entries */
3367 if (!targetIsInSortList(tle, sortop, sortlist))
3368 {
3369 SortGroupClause *sortcl = makeNode(SortGroupClause);
3370
3371 sortcl->tleSortGroupRef = assignSortGroupRef(tle, targetlist);
3372
3373 sortcl->eqop = eqop;
3374 sortcl->sortop = sortop;
3375 sortcl->hashable = hashable;
3376
3377 switch (sortby->sortby_nulls)
3378 {
3379 case SORTBY_NULLS_DEFAULT:
3380 /* NULLS FIRST is default for DESC; other way for ASC */
3381 sortcl->nulls_first = reverse;
3382 break;
3383 case SORTBY_NULLS_FIRST:
3384 sortcl->nulls_first = true;
3385 break;
3386 case SORTBY_NULLS_LAST:
3387 sortcl->nulls_first = false;
3388 break;
3389 default:
3390 elog(ERROR, "unrecognized sortby_nulls: %d",
3391 sortby->sortby_nulls);
3392 break;
3393 }
3394
3395 sortlist = lappend(sortlist, sortcl);
3396 }
3397
3398 return sortlist;
3399 }
3400
3401 /*
3402 * addTargetToGroupList
3403 * If the given targetlist entry isn't already in the SortGroupClause
3404 * list, add it to the end of the list, using default sort/group
3405 * semantics.
3406 *
3407 * This is very similar to addTargetToSortList, except that we allow the
3408 * case where only a grouping (equality) operator can be found, and that
3409 * the TLE is considered "already in the list" if it appears there with any
3410 * sorting semantics.
3411 *
3412 * location is the parse location to be fingered in event of trouble. Note
3413 * that we can't rely on exprLocation(tle->expr), because that might point
3414 * to a SELECT item that matches the GROUP BY item; it'd be pretty confusing
3415 * to report such a location.
3416 *
3417 * Returns the updated SortGroupClause list.
3418 */
3419 static List *
addTargetToGroupList(ParseState * pstate,TargetEntry * tle,List * grouplist,List * targetlist,int location)3420 addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
3421 List *grouplist, List *targetlist, int location)
3422 {
3423 Oid restype = exprType((Node *) tle->expr);
3424
3425 /* if tlist item is an UNKNOWN literal, change it to TEXT */
3426 if (restype == UNKNOWNOID)
3427 {
3428 tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
3429 restype, TEXTOID, -1,
3430 COERCION_IMPLICIT,
3431 COERCE_IMPLICIT_CAST,
3432 -1);
3433 restype = TEXTOID;
3434 }
3435
3436 /* avoid making duplicate grouplist entries */
3437 if (!targetIsInSortList(tle, InvalidOid, grouplist))
3438 {
3439 SortGroupClause *grpcl = makeNode(SortGroupClause);
3440 Oid sortop;
3441 Oid eqop;
3442 bool hashable;
3443 ParseCallbackState pcbstate;
3444
3445 setup_parser_errposition_callback(&pcbstate, pstate, location);
3446
3447 /* determine the eqop and optional sortop */
3448 get_sort_group_operators(restype,
3449 false, true, false,
3450 &sortop, &eqop, NULL,
3451 &hashable);
3452
3453 cancel_parser_errposition_callback(&pcbstate);
3454
3455 grpcl->tleSortGroupRef = assignSortGroupRef(tle, targetlist);
3456 grpcl->eqop = eqop;
3457 grpcl->sortop = sortop;
3458 grpcl->nulls_first = false; /* OK with or without sortop */
3459 grpcl->hashable = hashable;
3460
3461 grouplist = lappend(grouplist, grpcl);
3462 }
3463
3464 return grouplist;
3465 }
3466
3467 /*
3468 * assignSortGroupRef
3469 * Assign the targetentry an unused ressortgroupref, if it doesn't
3470 * already have one. Return the assigned or pre-existing refnumber.
3471 *
3472 * 'tlist' is the targetlist containing (or to contain) the given targetentry.
3473 */
3474 Index
assignSortGroupRef(TargetEntry * tle,List * tlist)3475 assignSortGroupRef(TargetEntry *tle, List *tlist)
3476 {
3477 Index maxRef;
3478 ListCell *l;
3479
3480 if (tle->ressortgroupref) /* already has one? */
3481 return tle->ressortgroupref;
3482
3483 /* easiest way to pick an unused refnumber: max used + 1 */
3484 maxRef = 0;
3485 foreach(l, tlist)
3486 {
3487 Index ref = ((TargetEntry *) lfirst(l))->ressortgroupref;
3488
3489 if (ref > maxRef)
3490 maxRef = ref;
3491 }
3492 tle->ressortgroupref = maxRef + 1;
3493 return tle->ressortgroupref;
3494 }
3495
3496 /*
3497 * targetIsInSortList
3498 * Is the given target item already in the sortlist?
3499 * If sortop is not InvalidOid, also test for a match to the sortop.
3500 *
3501 * It is not an oversight that this function ignores the nulls_first flag.
3502 * We check sortop when determining if an ORDER BY item is redundant with
3503 * earlier ORDER BY items, because it's conceivable that "ORDER BY
3504 * foo USING <, foo USING <<<" is not redundant, if <<< distinguishes
3505 * values that < considers equal. We need not check nulls_first
3506 * however, because a lower-order column with the same sortop but
3507 * opposite nulls direction is redundant. Also, we can consider
3508 * ORDER BY foo ASC, foo DESC redundant, so check for a commutator match.
3509 *
3510 * Works for both ordering and grouping lists (sortop would normally be
3511 * InvalidOid when considering grouping). Note that the main reason we need
3512 * this routine (and not just a quick test for nonzeroness of ressortgroupref)
3513 * is that a TLE might be in only one of the lists.
3514 */
3515 bool
targetIsInSortList(TargetEntry * tle,Oid sortop,List * sortList)3516 targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList)
3517 {
3518 Index ref = tle->ressortgroupref;
3519 ListCell *l;
3520
3521 /* no need to scan list if tle has no marker */
3522 if (ref == 0)
3523 return false;
3524
3525 foreach(l, sortList)
3526 {
3527 SortGroupClause *scl = (SortGroupClause *) lfirst(l);
3528
3529 if (scl->tleSortGroupRef == ref &&
3530 (sortop == InvalidOid ||
3531 sortop == scl->sortop ||
3532 sortop == get_commutator(scl->sortop)))
3533 return true;
3534 }
3535 return false;
3536 }
3537
3538 /*
3539 * findWindowClause
3540 * Find the named WindowClause in the list, or return NULL if not there
3541 */
3542 static WindowClause *
findWindowClause(List * wclist,const char * name)3543 findWindowClause(List *wclist, const char *name)
3544 {
3545 ListCell *l;
3546
3547 foreach(l, wclist)
3548 {
3549 WindowClause *wc = (WindowClause *) lfirst(l);
3550
3551 if (wc->name && strcmp(wc->name, name) == 0)
3552 return wc;
3553 }
3554
3555 return NULL;
3556 }
3557
3558 /*
3559 * transformFrameOffset
3560 * Process a window frame offset expression
3561 *
3562 * In RANGE mode, rangeopfamily is the sort opfamily for the input ORDER BY
3563 * column, and rangeopcintype is the input data type the sort operator is
3564 * registered with. We expect the in_range function to be registered with
3565 * that same type. (In binary-compatible cases, it might be different from
3566 * the input column's actual type, so we can't use that for the lookups.)
3567 * We'll return the OID of the in_range function to *inRangeFunc.
3568 */
3569 static Node *
transformFrameOffset(ParseState * pstate,int frameOptions,Oid rangeopfamily,Oid rangeopcintype,Oid * inRangeFunc,Node * clause)3570 transformFrameOffset(ParseState *pstate, int frameOptions,
3571 Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc,
3572 Node *clause)
3573 {
3574 const char *constructName = NULL;
3575 Node *node;
3576
3577 *inRangeFunc = InvalidOid; /* default result */
3578
3579 /* Quick exit if no offset expression */
3580 if (clause == NULL)
3581 return NULL;
3582
3583 if (frameOptions & FRAMEOPTION_ROWS)
3584 {
3585 /* Transform the raw expression tree */
3586 node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_ROWS);
3587
3588 /*
3589 * Like LIMIT clause, simply coerce to int8
3590 */
3591 constructName = "ROWS";
3592 node = coerce_to_specific_type(pstate, node, INT8OID, constructName);
3593 }
3594 else if (frameOptions & FRAMEOPTION_RANGE)
3595 {
3596 /*
3597 * We must look up the in_range support function that's to be used,
3598 * possibly choosing one of several, and coerce the "offset" value to
3599 * the appropriate input type.
3600 */
3601 Oid nodeType;
3602 Oid preferredType;
3603 int nfuncs = 0;
3604 int nmatches = 0;
3605 Oid selectedType = InvalidOid;
3606 Oid selectedFunc = InvalidOid;
3607 CatCList *proclist;
3608 int i;
3609
3610 /* Transform the raw expression tree */
3611 node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_RANGE);
3612 nodeType = exprType(node);
3613
3614 /*
3615 * If there are multiple candidates, we'll prefer the one that exactly
3616 * matches nodeType; or if nodeType is as yet unknown, prefer the one
3617 * that exactly matches the sort column type. (The second rule is
3618 * like what we do for "known_type operator unknown".)
3619 */
3620 preferredType = (nodeType != UNKNOWNOID) ? nodeType : rangeopcintype;
3621
3622 /* Find the in_range support functions applicable to this case */
3623 proclist = SearchSysCacheList2(AMPROCNUM,
3624 ObjectIdGetDatum(rangeopfamily),
3625 ObjectIdGetDatum(rangeopcintype));
3626 for (i = 0; i < proclist->n_members; i++)
3627 {
3628 HeapTuple proctup = &proclist->members[i]->tuple;
3629 Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);
3630
3631 /* The search will find all support proc types; ignore others */
3632 if (procform->amprocnum != BTINRANGE_PROC)
3633 continue;
3634 nfuncs++;
3635
3636 /* Ignore function if given value can't be coerced to that type */
3637 if (!can_coerce_type(1, &nodeType, &procform->amprocrighttype,
3638 COERCION_IMPLICIT))
3639 continue;
3640 nmatches++;
3641
3642 /* Remember preferred match, or any match if didn't find that */
3643 if (selectedType != preferredType)
3644 {
3645 selectedType = procform->amprocrighttype;
3646 selectedFunc = procform->amproc;
3647 }
3648 }
3649 ReleaseCatCacheList(proclist);
3650
3651 /*
3652 * Throw error if needed. It seems worth taking the trouble to
3653 * distinguish "no support at all" from "you didn't match any
3654 * available offset type".
3655 */
3656 if (nfuncs == 0)
3657 ereport(ERROR,
3658 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3659 errmsg("RANGE with offset PRECEDING/FOLLOWING is not supported for column type %s",
3660 format_type_be(rangeopcintype)),
3661 parser_errposition(pstate, exprLocation(node))));
3662 if (nmatches == 0)
3663 ereport(ERROR,
3664 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3665 errmsg("RANGE with offset PRECEDING/FOLLOWING is not supported for column type %s and offset type %s",
3666 format_type_be(rangeopcintype),
3667 format_type_be(nodeType)),
3668 errhint("Cast the offset value to an appropriate type."),
3669 parser_errposition(pstate, exprLocation(node))));
3670 if (nmatches != 1 && selectedType != preferredType)
3671 ereport(ERROR,
3672 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3673 errmsg("RANGE with offset PRECEDING/FOLLOWING has multiple interpretations for column type %s and offset type %s",
3674 format_type_be(rangeopcintype),
3675 format_type_be(nodeType)),
3676 errhint("Cast the offset value to the exact intended type."),
3677 parser_errposition(pstate, exprLocation(node))));
3678
3679 /* OK, coerce the offset to the right type */
3680 constructName = "RANGE";
3681 node = coerce_to_specific_type(pstate, node,
3682 selectedType, constructName);
3683 *inRangeFunc = selectedFunc;
3684 }
3685 else if (frameOptions & FRAMEOPTION_GROUPS)
3686 {
3687 /* Transform the raw expression tree */
3688 node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_GROUPS);
3689
3690 /*
3691 * Like LIMIT clause, simply coerce to int8
3692 */
3693 constructName = "GROUPS";
3694 node = coerce_to_specific_type(pstate, node, INT8OID, constructName);
3695 }
3696 else
3697 {
3698 Assert(false);
3699 node = NULL;
3700 }
3701
3702 /* Disallow variables in frame offsets */
3703 checkExprIsVarFree(pstate, node, constructName);
3704
3705 return node;
3706 }
3707