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