1 /*-------------------------------------------------------------------------
2 *
3 * parse_expr.c
4 * handle expressions in parser
5 *
6 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/parser/parse_expr.c
12 *
13 *-------------------------------------------------------------------------
14 */
15
16 #include "postgres.h"
17
18 #include "catalog/pg_type.h"
19 #include "commands/dbcommands.h"
20 #include "miscadmin.h"
21 #include "nodes/makefuncs.h"
22 #include "nodes/nodeFuncs.h"
23 #include "optimizer/optimizer.h"
24 #include "parser/analyze.h"
25 #include "parser/parse_agg.h"
26 #include "parser/parse_clause.h"
27 #include "parser/parse_coerce.h"
28 #include "parser/parse_collate.h"
29 #include "parser/parse_expr.h"
30 #include "parser/parse_func.h"
31 #include "parser/parse_oper.h"
32 #include "parser/parse_relation.h"
33 #include "parser/parse_target.h"
34 #include "parser/parse_type.h"
35 #include "utils/builtins.h"
36 #include "utils/date.h"
37 #include "utils/lsyscache.h"
38 #include "utils/timestamp.h"
39 #include "utils/xml.h"
40
41 /* GUC parameters */
42 bool Transform_null_equals = false;
43
44
45 static Node *transformExprRecurse(ParseState *pstate, Node *expr);
46 static Node *transformParamRef(ParseState *pstate, ParamRef *pref);
47 static Node *transformAExprOp(ParseState *pstate, A_Expr *a);
48 static Node *transformAExprOpAny(ParseState *pstate, A_Expr *a);
49 static Node *transformAExprOpAll(ParseState *pstate, A_Expr *a);
50 static Node *transformAExprDistinct(ParseState *pstate, A_Expr *a);
51 static Node *transformAExprNullIf(ParseState *pstate, A_Expr *a);
52 static Node *transformAExprIn(ParseState *pstate, A_Expr *a);
53 static Node *transformAExprBetween(ParseState *pstate, A_Expr *a);
54 static Node *transformBoolExpr(ParseState *pstate, BoolExpr *a);
55 static Node *transformFuncCall(ParseState *pstate, FuncCall *fn);
56 static Node *transformMultiAssignRef(ParseState *pstate, MultiAssignRef *maref);
57 static Node *transformCaseExpr(ParseState *pstate, CaseExpr *c);
58 static Node *transformSubLink(ParseState *pstate, SubLink *sublink);
59 static Node *transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
60 Oid array_type, Oid element_type, int32 typmod);
61 static Node *transformRowExpr(ParseState *pstate, RowExpr *r, bool allowDefault);
62 static Node *transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c);
63 static Node *transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m);
64 static Node *transformSQLValueFunction(ParseState *pstate,
65 SQLValueFunction *svf);
66 static Node *transformXmlExpr(ParseState *pstate, XmlExpr *x);
67 static Node *transformXmlSerialize(ParseState *pstate, XmlSerialize *xs);
68 static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
69 static Node *transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr);
70 static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
71 static Node *transformWholeRowRef(ParseState *pstate,
72 ParseNamespaceItem *nsitem,
73 int sublevels_up, int location);
74 static Node *transformIndirection(ParseState *pstate, A_Indirection *ind);
75 static Node *transformTypeCast(ParseState *pstate, TypeCast *tc);
76 static Node *transformCollateClause(ParseState *pstate, CollateClause *c);
77 static Node *make_row_comparison_op(ParseState *pstate, List *opname,
78 List *largs, List *rargs, int location);
79 static Node *make_row_distinct_op(ParseState *pstate, List *opname,
80 RowExpr *lrow, RowExpr *rrow, int location);
81 static Expr *make_distinct_op(ParseState *pstate, List *opname,
82 Node *ltree, Node *rtree, int location);
83 static Node *make_nulltest_from_distinct(ParseState *pstate,
84 A_Expr *distincta, Node *arg);
85
86
87 /*
88 * transformExpr -
89 * Analyze and transform expressions. Type checking and type casting is
90 * done here. This processing converts the raw grammar output into
91 * expression trees with fully determined semantics.
92 */
93 Node *
transformExpr(ParseState * pstate,Node * expr,ParseExprKind exprKind)94 transformExpr(ParseState *pstate, Node *expr, ParseExprKind exprKind)
95 {
96 Node *result;
97 ParseExprKind sv_expr_kind;
98
99 /* Save and restore identity of expression type we're parsing */
100 Assert(exprKind != EXPR_KIND_NONE);
101 sv_expr_kind = pstate->p_expr_kind;
102 pstate->p_expr_kind = exprKind;
103
104 result = transformExprRecurse(pstate, expr);
105
106 pstate->p_expr_kind = sv_expr_kind;
107
108 return result;
109 }
110
111 static Node *
transformExprRecurse(ParseState * pstate,Node * expr)112 transformExprRecurse(ParseState *pstate, Node *expr)
113 {
114 Node *result;
115
116 if (expr == NULL)
117 return NULL;
118
119 /* Guard against stack overflow due to overly complex expressions */
120 check_stack_depth();
121
122 switch (nodeTag(expr))
123 {
124 case T_ColumnRef:
125 result = transformColumnRef(pstate, (ColumnRef *) expr);
126 break;
127
128 case T_ParamRef:
129 result = transformParamRef(pstate, (ParamRef *) expr);
130 break;
131
132 case T_A_Const:
133 {
134 A_Const *con = (A_Const *) expr;
135 Value *val = &con->val;
136
137 result = (Node *) make_const(pstate, val, con->location);
138 break;
139 }
140
141 case T_A_Indirection:
142 result = transformIndirection(pstate, (A_Indirection *) expr);
143 break;
144
145 case T_A_ArrayExpr:
146 result = transformArrayExpr(pstate, (A_ArrayExpr *) expr,
147 InvalidOid, InvalidOid, -1);
148 break;
149
150 case T_TypeCast:
151 result = transformTypeCast(pstate, (TypeCast *) expr);
152 break;
153
154 case T_CollateClause:
155 result = transformCollateClause(pstate, (CollateClause *) expr);
156 break;
157
158 case T_A_Expr:
159 {
160 A_Expr *a = (A_Expr *) expr;
161
162 switch (a->kind)
163 {
164 case AEXPR_OP:
165 result = transformAExprOp(pstate, a);
166 break;
167 case AEXPR_OP_ANY:
168 result = transformAExprOpAny(pstate, a);
169 break;
170 case AEXPR_OP_ALL:
171 result = transformAExprOpAll(pstate, a);
172 break;
173 case AEXPR_DISTINCT:
174 case AEXPR_NOT_DISTINCT:
175 result = transformAExprDistinct(pstate, a);
176 break;
177 case AEXPR_NULLIF:
178 result = transformAExprNullIf(pstate, a);
179 break;
180 case AEXPR_IN:
181 result = transformAExprIn(pstate, a);
182 break;
183 case AEXPR_LIKE:
184 case AEXPR_ILIKE:
185 case AEXPR_SIMILAR:
186 /* we can transform these just like AEXPR_OP */
187 result = transformAExprOp(pstate, a);
188 break;
189 case AEXPR_BETWEEN:
190 case AEXPR_NOT_BETWEEN:
191 case AEXPR_BETWEEN_SYM:
192 case AEXPR_NOT_BETWEEN_SYM:
193 result = transformAExprBetween(pstate, a);
194 break;
195 default:
196 elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
197 result = NULL; /* keep compiler quiet */
198 break;
199 }
200 break;
201 }
202
203 case T_BoolExpr:
204 result = transformBoolExpr(pstate, (BoolExpr *) expr);
205 break;
206
207 case T_FuncCall:
208 result = transformFuncCall(pstate, (FuncCall *) expr);
209 break;
210
211 case T_MultiAssignRef:
212 result = transformMultiAssignRef(pstate, (MultiAssignRef *) expr);
213 break;
214
215 case T_GroupingFunc:
216 result = transformGroupingFunc(pstate, (GroupingFunc *) expr);
217 break;
218
219 case T_NamedArgExpr:
220 {
221 NamedArgExpr *na = (NamedArgExpr *) expr;
222
223 na->arg = (Expr *) transformExprRecurse(pstate, (Node *) na->arg);
224 result = expr;
225 break;
226 }
227
228 case T_SubLink:
229 result = transformSubLink(pstate, (SubLink *) expr);
230 break;
231
232 case T_CaseExpr:
233 result = transformCaseExpr(pstate, (CaseExpr *) expr);
234 break;
235
236 case T_RowExpr:
237 result = transformRowExpr(pstate, (RowExpr *) expr, false);
238 break;
239
240 case T_CoalesceExpr:
241 result = transformCoalesceExpr(pstate, (CoalesceExpr *) expr);
242 break;
243
244 case T_MinMaxExpr:
245 result = transformMinMaxExpr(pstate, (MinMaxExpr *) expr);
246 break;
247
248 case T_SQLValueFunction:
249 result = transformSQLValueFunction(pstate,
250 (SQLValueFunction *) expr);
251 break;
252
253 case T_XmlExpr:
254 result = transformXmlExpr(pstate, (XmlExpr *) expr);
255 break;
256
257 case T_XmlSerialize:
258 result = transformXmlSerialize(pstate, (XmlSerialize *) expr);
259 break;
260
261 case T_NullTest:
262 {
263 NullTest *n = (NullTest *) expr;
264
265 n->arg = (Expr *) transformExprRecurse(pstate, (Node *) n->arg);
266 /* the argument can be any type, so don't coerce it */
267 n->argisrow = type_is_rowtype(exprType((Node *) n->arg));
268 result = expr;
269 break;
270 }
271
272 case T_BooleanTest:
273 result = transformBooleanTest(pstate, (BooleanTest *) expr);
274 break;
275
276 case T_CurrentOfExpr:
277 result = transformCurrentOfExpr(pstate, (CurrentOfExpr *) expr);
278 break;
279
280 /*
281 * In all places where DEFAULT is legal, the caller should have
282 * processed it rather than passing it to transformExpr().
283 */
284 case T_SetToDefault:
285 ereport(ERROR,
286 (errcode(ERRCODE_SYNTAX_ERROR),
287 errmsg("DEFAULT is not allowed in this context"),
288 parser_errposition(pstate,
289 ((SetToDefault *) expr)->location)));
290 break;
291
292 /*
293 * CaseTestExpr doesn't require any processing; it is only
294 * injected into parse trees in a fully-formed state.
295 *
296 * Ordinarily we should not see a Var here, but it is convenient
297 * for transformJoinUsingClause() to create untransformed operator
298 * trees containing already-transformed Vars. The best
299 * alternative would be to deconstruct and reconstruct column
300 * references, which seems expensively pointless. So allow it.
301 */
302 case T_CaseTestExpr:
303 case T_Var:
304 {
305 result = (Node *) expr;
306 break;
307 }
308
309 default:
310 /* should not reach here */
311 elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
312 result = NULL; /* keep compiler quiet */
313 break;
314 }
315
316 return result;
317 }
318
319 /*
320 * helper routine for delivering "column does not exist" error message
321 *
322 * (Usually we don't have to work this hard, but the general case of field
323 * selection from an arbitrary node needs it.)
324 */
325 static void
unknown_attribute(ParseState * pstate,Node * relref,const char * attname,int location)326 unknown_attribute(ParseState *pstate, Node *relref, const char *attname,
327 int location)
328 {
329 RangeTblEntry *rte;
330
331 if (IsA(relref, Var) &&
332 ((Var *) relref)->varattno == InvalidAttrNumber)
333 {
334 /* Reference the RTE by alias not by actual table name */
335 rte = GetRTEByRangeTablePosn(pstate,
336 ((Var *) relref)->varno,
337 ((Var *) relref)->varlevelsup);
338 ereport(ERROR,
339 (errcode(ERRCODE_UNDEFINED_COLUMN),
340 errmsg("column %s.%s does not exist",
341 rte->eref->aliasname, attname),
342 parser_errposition(pstate, location)));
343 }
344 else
345 {
346 /* Have to do it by reference to the type of the expression */
347 Oid relTypeId = exprType(relref);
348
349 if (ISCOMPLEX(relTypeId))
350 ereport(ERROR,
351 (errcode(ERRCODE_UNDEFINED_COLUMN),
352 errmsg("column \"%s\" not found in data type %s",
353 attname, format_type_be(relTypeId)),
354 parser_errposition(pstate, location)));
355 else if (relTypeId == RECORDOID)
356 ereport(ERROR,
357 (errcode(ERRCODE_UNDEFINED_COLUMN),
358 errmsg("could not identify column \"%s\" in record data type",
359 attname),
360 parser_errposition(pstate, location)));
361 else
362 ereport(ERROR,
363 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
364 errmsg("column notation .%s applied to type %s, "
365 "which is not a composite type",
366 attname, format_type_be(relTypeId)),
367 parser_errposition(pstate, location)));
368 }
369 }
370
371 static Node *
transformIndirection(ParseState * pstate,A_Indirection * ind)372 transformIndirection(ParseState *pstate, A_Indirection *ind)
373 {
374 Node *last_srf = pstate->p_last_srf;
375 Node *result = transformExprRecurse(pstate, ind->arg);
376 List *subscripts = NIL;
377 int location = exprLocation(result);
378 ListCell *i;
379
380 /*
381 * We have to split any field-selection operations apart from
382 * subscripting. Adjacent A_Indices nodes have to be treated as a single
383 * multidimensional subscript operation.
384 */
385 foreach(i, ind->indirection)
386 {
387 Node *n = lfirst(i);
388
389 if (IsA(n, A_Indices))
390 subscripts = lappend(subscripts, n);
391 else if (IsA(n, A_Star))
392 {
393 ereport(ERROR,
394 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
395 errmsg("row expansion via \"*\" is not supported here"),
396 parser_errposition(pstate, location)));
397 }
398 else
399 {
400 Node *newresult;
401
402 Assert(IsA(n, String));
403
404 /* process subscripts before this field selection */
405 if (subscripts)
406 result = (Node *) transformContainerSubscripts(pstate,
407 result,
408 exprType(result),
409 exprTypmod(result),
410 subscripts,
411 false);
412 subscripts = NIL;
413
414 newresult = ParseFuncOrColumn(pstate,
415 list_make1(n),
416 list_make1(result),
417 last_srf,
418 NULL,
419 false,
420 location);
421 if (newresult == NULL)
422 unknown_attribute(pstate, result, strVal(n), location);
423 result = newresult;
424 }
425 }
426 /* process trailing subscripts, if any */
427 if (subscripts)
428 result = (Node *) transformContainerSubscripts(pstate,
429 result,
430 exprType(result),
431 exprTypmod(result),
432 subscripts,
433 false);
434
435 return result;
436 }
437
438 /*
439 * Transform a ColumnRef.
440 *
441 * If you find yourself changing this code, see also ExpandColumnRefStar.
442 */
443 static Node *
transformColumnRef(ParseState * pstate,ColumnRef * cref)444 transformColumnRef(ParseState *pstate, ColumnRef *cref)
445 {
446 Node *node = NULL;
447 char *nspname = NULL;
448 char *relname = NULL;
449 char *colname = NULL;
450 ParseNamespaceItem *nsitem;
451 int levels_up;
452 enum
453 {
454 CRERR_NO_COLUMN,
455 CRERR_NO_RTE,
456 CRERR_WRONG_DB,
457 CRERR_TOO_MANY
458 } crerr = CRERR_NO_COLUMN;
459 const char *err;
460
461 /*
462 * Check to see if the column reference is in an invalid place within the
463 * query. We allow column references in most places, except in default
464 * expressions and partition bound expressions.
465 */
466 err = NULL;
467 switch (pstate->p_expr_kind)
468 {
469 case EXPR_KIND_NONE:
470 Assert(false); /* can't happen */
471 break;
472 case EXPR_KIND_OTHER:
473 case EXPR_KIND_JOIN_ON:
474 case EXPR_KIND_JOIN_USING:
475 case EXPR_KIND_FROM_SUBSELECT:
476 case EXPR_KIND_FROM_FUNCTION:
477 case EXPR_KIND_WHERE:
478 case EXPR_KIND_POLICY:
479 case EXPR_KIND_HAVING:
480 case EXPR_KIND_FILTER:
481 case EXPR_KIND_WINDOW_PARTITION:
482 case EXPR_KIND_WINDOW_ORDER:
483 case EXPR_KIND_WINDOW_FRAME_RANGE:
484 case EXPR_KIND_WINDOW_FRAME_ROWS:
485 case EXPR_KIND_WINDOW_FRAME_GROUPS:
486 case EXPR_KIND_SELECT_TARGET:
487 case EXPR_KIND_INSERT_TARGET:
488 case EXPR_KIND_UPDATE_SOURCE:
489 case EXPR_KIND_UPDATE_TARGET:
490 case EXPR_KIND_GROUP_BY:
491 case EXPR_KIND_ORDER_BY:
492 case EXPR_KIND_DISTINCT_ON:
493 case EXPR_KIND_LIMIT:
494 case EXPR_KIND_OFFSET:
495 case EXPR_KIND_RETURNING:
496 case EXPR_KIND_VALUES:
497 case EXPR_KIND_VALUES_SINGLE:
498 case EXPR_KIND_CHECK_CONSTRAINT:
499 case EXPR_KIND_DOMAIN_CHECK:
500 case EXPR_KIND_FUNCTION_DEFAULT:
501 case EXPR_KIND_INDEX_EXPRESSION:
502 case EXPR_KIND_INDEX_PREDICATE:
503 case EXPR_KIND_STATS_EXPRESSION:
504 case EXPR_KIND_ALTER_COL_TRANSFORM:
505 case EXPR_KIND_EXECUTE_PARAMETER:
506 case EXPR_KIND_TRIGGER_WHEN:
507 case EXPR_KIND_PARTITION_EXPRESSION:
508 case EXPR_KIND_CALL_ARGUMENT:
509 case EXPR_KIND_COPY_WHERE:
510 case EXPR_KIND_GENERATED_COLUMN:
511 case EXPR_KIND_CYCLE_MARK:
512 /* okay */
513 break;
514
515 case EXPR_KIND_COLUMN_DEFAULT:
516 err = _("cannot use column reference in DEFAULT expression");
517 break;
518 case EXPR_KIND_PARTITION_BOUND:
519 err = _("cannot use column reference in partition bound expression");
520 break;
521
522 /*
523 * There is intentionally no default: case here, so that the
524 * compiler will warn if we add a new ParseExprKind without
525 * extending this switch. If we do see an unrecognized value at
526 * runtime, the behavior will be the same as for EXPR_KIND_OTHER,
527 * which is sane anyway.
528 */
529 }
530 if (err)
531 ereport(ERROR,
532 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
533 errmsg_internal("%s", err),
534 parser_errposition(pstate, cref->location)));
535
536 /*
537 * Give the PreParseColumnRefHook, if any, first shot. If it returns
538 * non-null then that's all, folks.
539 */
540 if (pstate->p_pre_columnref_hook != NULL)
541 {
542 node = pstate->p_pre_columnref_hook(pstate, cref);
543 if (node != NULL)
544 return node;
545 }
546
547 /*----------
548 * The allowed syntaxes are:
549 *
550 * A First try to resolve as unqualified column name;
551 * if no luck, try to resolve as unqualified table name (A.*).
552 * A.B A is an unqualified table name; B is either a
553 * column or function name (trying column name first).
554 * A.B.C schema A, table B, col or func name C.
555 * A.B.C.D catalog A, schema B, table C, col or func D.
556 * A.* A is an unqualified table name; means whole-row value.
557 * A.B.* whole-row value of table B in schema A.
558 * A.B.C.* whole-row value of table C in schema B in catalog A.
559 *
560 * We do not need to cope with bare "*"; that will only be accepted by
561 * the grammar at the top level of a SELECT list, and transformTargetList
562 * will take care of it before it ever gets here. Also, "A.*" etc will
563 * be expanded by transformTargetList if they appear at SELECT top level,
564 * so here we are only going to see them as function or operator inputs.
565 *
566 * Currently, if a catalog name is given then it must equal the current
567 * database name; we check it here and then discard it.
568 *----------
569 */
570 switch (list_length(cref->fields))
571 {
572 case 1:
573 {
574 Node *field1 = (Node *) linitial(cref->fields);
575
576 Assert(IsA(field1, String));
577 colname = strVal(field1);
578
579 /* Try to identify as an unqualified column */
580 node = colNameToVar(pstate, colname, false, cref->location);
581
582 if (node == NULL)
583 {
584 /*
585 * Not known as a column of any range-table entry.
586 *
587 * Try to find the name as a relation. Note that only
588 * relations already entered into the rangetable will be
589 * recognized.
590 *
591 * This is a hack for backwards compatibility with
592 * PostQUEL-inspired syntax. The preferred form now is
593 * "rel.*".
594 */
595 nsitem = refnameNamespaceItem(pstate, NULL, colname,
596 cref->location,
597 &levels_up);
598 if (nsitem)
599 node = transformWholeRowRef(pstate, nsitem, levels_up,
600 cref->location);
601 }
602 break;
603 }
604 case 2:
605 {
606 Node *field1 = (Node *) linitial(cref->fields);
607 Node *field2 = (Node *) lsecond(cref->fields);
608
609 Assert(IsA(field1, String));
610 relname = strVal(field1);
611
612 /* Locate the referenced nsitem */
613 nsitem = refnameNamespaceItem(pstate, nspname, relname,
614 cref->location,
615 &levels_up);
616 if (nsitem == NULL)
617 {
618 crerr = CRERR_NO_RTE;
619 break;
620 }
621
622 /* Whole-row reference? */
623 if (IsA(field2, A_Star))
624 {
625 node = transformWholeRowRef(pstate, nsitem, levels_up,
626 cref->location);
627 break;
628 }
629
630 Assert(IsA(field2, String));
631 colname = strVal(field2);
632
633 /* Try to identify as a column of the nsitem */
634 node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
635 cref->location);
636 if (node == NULL)
637 {
638 /* Try it as a function call on the whole row */
639 node = transformWholeRowRef(pstate, nsitem, levels_up,
640 cref->location);
641 node = ParseFuncOrColumn(pstate,
642 list_make1(makeString(colname)),
643 list_make1(node),
644 pstate->p_last_srf,
645 NULL,
646 false,
647 cref->location);
648 }
649 break;
650 }
651 case 3:
652 {
653 Node *field1 = (Node *) linitial(cref->fields);
654 Node *field2 = (Node *) lsecond(cref->fields);
655 Node *field3 = (Node *) lthird(cref->fields);
656
657 Assert(IsA(field1, String));
658 nspname = strVal(field1);
659 Assert(IsA(field2, String));
660 relname = strVal(field2);
661
662 /* Locate the referenced nsitem */
663 nsitem = refnameNamespaceItem(pstate, nspname, relname,
664 cref->location,
665 &levels_up);
666 if (nsitem == NULL)
667 {
668 crerr = CRERR_NO_RTE;
669 break;
670 }
671
672 /* Whole-row reference? */
673 if (IsA(field3, A_Star))
674 {
675 node = transformWholeRowRef(pstate, nsitem, levels_up,
676 cref->location);
677 break;
678 }
679
680 Assert(IsA(field3, String));
681 colname = strVal(field3);
682
683 /* Try to identify as a column of the nsitem */
684 node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
685 cref->location);
686 if (node == NULL)
687 {
688 /* Try it as a function call on the whole row */
689 node = transformWholeRowRef(pstate, nsitem, levels_up,
690 cref->location);
691 node = ParseFuncOrColumn(pstate,
692 list_make1(makeString(colname)),
693 list_make1(node),
694 pstate->p_last_srf,
695 NULL,
696 false,
697 cref->location);
698 }
699 break;
700 }
701 case 4:
702 {
703 Node *field1 = (Node *) linitial(cref->fields);
704 Node *field2 = (Node *) lsecond(cref->fields);
705 Node *field3 = (Node *) lthird(cref->fields);
706 Node *field4 = (Node *) lfourth(cref->fields);
707 char *catname;
708
709 Assert(IsA(field1, String));
710 catname = strVal(field1);
711 Assert(IsA(field2, String));
712 nspname = strVal(field2);
713 Assert(IsA(field3, String));
714 relname = strVal(field3);
715
716 /*
717 * We check the catalog name and then ignore it.
718 */
719 if (strcmp(catname, get_database_name(MyDatabaseId)) != 0)
720 {
721 crerr = CRERR_WRONG_DB;
722 break;
723 }
724
725 /* Locate the referenced nsitem */
726 nsitem = refnameNamespaceItem(pstate, nspname, relname,
727 cref->location,
728 &levels_up);
729 if (nsitem == NULL)
730 {
731 crerr = CRERR_NO_RTE;
732 break;
733 }
734
735 /* Whole-row reference? */
736 if (IsA(field4, A_Star))
737 {
738 node = transformWholeRowRef(pstate, nsitem, levels_up,
739 cref->location);
740 break;
741 }
742
743 Assert(IsA(field4, String));
744 colname = strVal(field4);
745
746 /* Try to identify as a column of the nsitem */
747 node = scanNSItemForColumn(pstate, nsitem, levels_up, colname,
748 cref->location);
749 if (node == NULL)
750 {
751 /* Try it as a function call on the whole row */
752 node = transformWholeRowRef(pstate, nsitem, levels_up,
753 cref->location);
754 node = ParseFuncOrColumn(pstate,
755 list_make1(makeString(colname)),
756 list_make1(node),
757 pstate->p_last_srf,
758 NULL,
759 false,
760 cref->location);
761 }
762 break;
763 }
764 default:
765 crerr = CRERR_TOO_MANY; /* too many dotted names */
766 break;
767 }
768
769 /*
770 * Now give the PostParseColumnRefHook, if any, a chance. We pass the
771 * translation-so-far so that it can throw an error if it wishes in the
772 * case that it has a conflicting interpretation of the ColumnRef. (If it
773 * just translates anyway, we'll throw an error, because we can't undo
774 * whatever effects the preceding steps may have had on the pstate.) If it
775 * returns NULL, use the standard translation, or throw a suitable error
776 * if there is none.
777 */
778 if (pstate->p_post_columnref_hook != NULL)
779 {
780 Node *hookresult;
781
782 hookresult = pstate->p_post_columnref_hook(pstate, cref, node);
783 if (node == NULL)
784 node = hookresult;
785 else if (hookresult != NULL)
786 ereport(ERROR,
787 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
788 errmsg("column reference \"%s\" is ambiguous",
789 NameListToString(cref->fields)),
790 parser_errposition(pstate, cref->location)));
791 }
792
793 /*
794 * Throw error if no translation found.
795 */
796 if (node == NULL)
797 {
798 switch (crerr)
799 {
800 case CRERR_NO_COLUMN:
801 errorMissingColumn(pstate, relname, colname, cref->location);
802 break;
803 case CRERR_NO_RTE:
804 errorMissingRTE(pstate, makeRangeVar(nspname, relname,
805 cref->location));
806 break;
807 case CRERR_WRONG_DB:
808 ereport(ERROR,
809 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
810 errmsg("cross-database references are not implemented: %s",
811 NameListToString(cref->fields)),
812 parser_errposition(pstate, cref->location)));
813 break;
814 case CRERR_TOO_MANY:
815 ereport(ERROR,
816 (errcode(ERRCODE_SYNTAX_ERROR),
817 errmsg("improper qualified name (too many dotted names): %s",
818 NameListToString(cref->fields)),
819 parser_errposition(pstate, cref->location)));
820 break;
821 }
822 }
823
824 return node;
825 }
826
827 static Node *
transformParamRef(ParseState * pstate,ParamRef * pref)828 transformParamRef(ParseState *pstate, ParamRef *pref)
829 {
830 Node *result;
831
832 /*
833 * The core parser knows nothing about Params. If a hook is supplied,
834 * call it. If not, or if the hook returns NULL, throw a generic error.
835 */
836 if (pstate->p_paramref_hook != NULL)
837 result = pstate->p_paramref_hook(pstate, pref);
838 else
839 result = NULL;
840
841 if (result == NULL)
842 ereport(ERROR,
843 (errcode(ERRCODE_UNDEFINED_PARAMETER),
844 errmsg("there is no parameter $%d", pref->number),
845 parser_errposition(pstate, pref->location)));
846
847 return result;
848 }
849
850 /* Test whether an a_expr is a plain NULL constant or not */
851 static bool
exprIsNullConstant(Node * arg)852 exprIsNullConstant(Node *arg)
853 {
854 if (arg && IsA(arg, A_Const))
855 {
856 A_Const *con = (A_Const *) arg;
857
858 if (con->val.type == T_Null)
859 return true;
860 }
861 return false;
862 }
863
864 static Node *
transformAExprOp(ParseState * pstate,A_Expr * a)865 transformAExprOp(ParseState *pstate, A_Expr *a)
866 {
867 Node *lexpr = a->lexpr;
868 Node *rexpr = a->rexpr;
869 Node *result;
870
871 /*
872 * Special-case "foo = NULL" and "NULL = foo" for compatibility with
873 * standards-broken products (like Microsoft's). Turn these into IS NULL
874 * exprs. (If either side is a CaseTestExpr, then the expression was
875 * generated internally from a CASE-WHEN expression, and
876 * transform_null_equals does not apply.)
877 */
878 if (Transform_null_equals &&
879 list_length(a->name) == 1 &&
880 strcmp(strVal(linitial(a->name)), "=") == 0 &&
881 (exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)) &&
882 (!IsA(lexpr, CaseTestExpr) && !IsA(rexpr, CaseTestExpr)))
883 {
884 NullTest *n = makeNode(NullTest);
885
886 n->nulltesttype = IS_NULL;
887 n->location = a->location;
888
889 if (exprIsNullConstant(lexpr))
890 n->arg = (Expr *) rexpr;
891 else
892 n->arg = (Expr *) lexpr;
893
894 result = transformExprRecurse(pstate, (Node *) n);
895 }
896 else if (lexpr && IsA(lexpr, RowExpr) &&
897 rexpr && IsA(rexpr, SubLink) &&
898 ((SubLink *) rexpr)->subLinkType == EXPR_SUBLINK)
899 {
900 /*
901 * Convert "row op subselect" into a ROWCOMPARE sublink. Formerly the
902 * grammar did this, but now that a row construct is allowed anywhere
903 * in expressions, it's easier to do it here.
904 */
905 SubLink *s = (SubLink *) rexpr;
906
907 s->subLinkType = ROWCOMPARE_SUBLINK;
908 s->testexpr = lexpr;
909 s->operName = a->name;
910 s->location = a->location;
911 result = transformExprRecurse(pstate, (Node *) s);
912 }
913 else if (lexpr && IsA(lexpr, RowExpr) &&
914 rexpr && IsA(rexpr, RowExpr))
915 {
916 /* ROW() op ROW() is handled specially */
917 lexpr = transformExprRecurse(pstate, lexpr);
918 rexpr = transformExprRecurse(pstate, rexpr);
919
920 result = make_row_comparison_op(pstate,
921 a->name,
922 castNode(RowExpr, lexpr)->args,
923 castNode(RowExpr, rexpr)->args,
924 a->location);
925 }
926 else
927 {
928 /* Ordinary scalar operator */
929 Node *last_srf = pstate->p_last_srf;
930
931 lexpr = transformExprRecurse(pstate, lexpr);
932 rexpr = transformExprRecurse(pstate, rexpr);
933
934 result = (Node *) make_op(pstate,
935 a->name,
936 lexpr,
937 rexpr,
938 last_srf,
939 a->location);
940 }
941
942 return result;
943 }
944
945 static Node *
transformAExprOpAny(ParseState * pstate,A_Expr * a)946 transformAExprOpAny(ParseState *pstate, A_Expr *a)
947 {
948 Node *lexpr = transformExprRecurse(pstate, a->lexpr);
949 Node *rexpr = transformExprRecurse(pstate, a->rexpr);
950
951 return (Node *) make_scalar_array_op(pstate,
952 a->name,
953 true,
954 lexpr,
955 rexpr,
956 a->location);
957 }
958
959 static Node *
transformAExprOpAll(ParseState * pstate,A_Expr * a)960 transformAExprOpAll(ParseState *pstate, A_Expr *a)
961 {
962 Node *lexpr = transformExprRecurse(pstate, a->lexpr);
963 Node *rexpr = transformExprRecurse(pstate, a->rexpr);
964
965 return (Node *) make_scalar_array_op(pstate,
966 a->name,
967 false,
968 lexpr,
969 rexpr,
970 a->location);
971 }
972
973 static Node *
transformAExprDistinct(ParseState * pstate,A_Expr * a)974 transformAExprDistinct(ParseState *pstate, A_Expr *a)
975 {
976 Node *lexpr = a->lexpr;
977 Node *rexpr = a->rexpr;
978 Node *result;
979
980 /*
981 * If either input is an undecorated NULL literal, transform to a NullTest
982 * on the other input. That's simpler to process than a full DistinctExpr,
983 * and it avoids needing to require that the datatype have an = operator.
984 */
985 if (exprIsNullConstant(rexpr))
986 return make_nulltest_from_distinct(pstate, a, lexpr);
987 if (exprIsNullConstant(lexpr))
988 return make_nulltest_from_distinct(pstate, a, rexpr);
989
990 lexpr = transformExprRecurse(pstate, lexpr);
991 rexpr = transformExprRecurse(pstate, rexpr);
992
993 if (lexpr && IsA(lexpr, RowExpr) &&
994 rexpr && IsA(rexpr, RowExpr))
995 {
996 /* ROW() op ROW() is handled specially */
997 result = make_row_distinct_op(pstate, a->name,
998 (RowExpr *) lexpr,
999 (RowExpr *) rexpr,
1000 a->location);
1001 }
1002 else
1003 {
1004 /* Ordinary scalar operator */
1005 result = (Node *) make_distinct_op(pstate,
1006 a->name,
1007 lexpr,
1008 rexpr,
1009 a->location);
1010 }
1011
1012 /*
1013 * If it's NOT DISTINCT, we first build a DistinctExpr and then stick a
1014 * NOT on top.
1015 */
1016 if (a->kind == AEXPR_NOT_DISTINCT)
1017 result = (Node *) makeBoolExpr(NOT_EXPR,
1018 list_make1(result),
1019 a->location);
1020
1021 return result;
1022 }
1023
1024 static Node *
transformAExprNullIf(ParseState * pstate,A_Expr * a)1025 transformAExprNullIf(ParseState *pstate, A_Expr *a)
1026 {
1027 Node *lexpr = transformExprRecurse(pstate, a->lexpr);
1028 Node *rexpr = transformExprRecurse(pstate, a->rexpr);
1029 OpExpr *result;
1030
1031 result = (OpExpr *) make_op(pstate,
1032 a->name,
1033 lexpr,
1034 rexpr,
1035 pstate->p_last_srf,
1036 a->location);
1037
1038 /*
1039 * The comparison operator itself should yield boolean ...
1040 */
1041 if (result->opresulttype != BOOLOID)
1042 ereport(ERROR,
1043 (errcode(ERRCODE_DATATYPE_MISMATCH),
1044 errmsg("NULLIF requires = operator to yield boolean"),
1045 parser_errposition(pstate, a->location)));
1046 if (result->opretset)
1047 ereport(ERROR,
1048 (errcode(ERRCODE_DATATYPE_MISMATCH),
1049 /* translator: %s is name of a SQL construct, eg NULLIF */
1050 errmsg("%s must not return a set", "NULLIF"),
1051 parser_errposition(pstate, a->location)));
1052
1053 /*
1054 * ... but the NullIfExpr will yield the first operand's type.
1055 */
1056 result->opresulttype = exprType((Node *) linitial(result->args));
1057
1058 /*
1059 * We rely on NullIfExpr and OpExpr being the same struct
1060 */
1061 NodeSetTag(result, T_NullIfExpr);
1062
1063 return (Node *) result;
1064 }
1065
1066 static Node *
transformAExprIn(ParseState * pstate,A_Expr * a)1067 transformAExprIn(ParseState *pstate, A_Expr *a)
1068 {
1069 Node *result = NULL;
1070 Node *lexpr;
1071 List *rexprs;
1072 List *rvars;
1073 List *rnonvars;
1074 bool useOr;
1075 ListCell *l;
1076
1077 /*
1078 * If the operator is <>, combine with AND not OR.
1079 */
1080 if (strcmp(strVal(linitial(a->name)), "<>") == 0)
1081 useOr = false;
1082 else
1083 useOr = true;
1084
1085 /*
1086 * We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
1087 * possible if there is a suitable array type available. If not, we fall
1088 * back to a boolean condition tree with multiple copies of the lefthand
1089 * expression. Also, any IN-list items that contain Vars are handled as
1090 * separate boolean conditions, because that gives the planner more scope
1091 * for optimization on such clauses.
1092 *
1093 * First step: transform all the inputs, and detect whether any contain
1094 * Vars.
1095 */
1096 lexpr = transformExprRecurse(pstate, a->lexpr);
1097 rexprs = rvars = rnonvars = NIL;
1098 foreach(l, (List *) a->rexpr)
1099 {
1100 Node *rexpr = transformExprRecurse(pstate, lfirst(l));
1101
1102 rexprs = lappend(rexprs, rexpr);
1103 if (contain_vars_of_level(rexpr, 0))
1104 rvars = lappend(rvars, rexpr);
1105 else
1106 rnonvars = lappend(rnonvars, rexpr);
1107 }
1108
1109 /*
1110 * ScalarArrayOpExpr is only going to be useful if there's more than one
1111 * non-Var righthand item.
1112 */
1113 if (list_length(rnonvars) > 1)
1114 {
1115 List *allexprs;
1116 Oid scalar_type;
1117 Oid array_type;
1118
1119 /*
1120 * Try to select a common type for the array elements. Note that
1121 * since the LHS' type is first in the list, it will be preferred when
1122 * there is doubt (eg, when all the RHS items are unknown literals).
1123 *
1124 * Note: use list_concat here not lcons, to avoid damaging rnonvars.
1125 */
1126 allexprs = list_concat(list_make1(lexpr), rnonvars);
1127 scalar_type = select_common_type(pstate, allexprs, NULL, NULL);
1128
1129 /*
1130 * Do we have an array type to use? Aside from the case where there
1131 * isn't one, we don't risk using ScalarArrayOpExpr when the common
1132 * type is RECORD, because the RowExpr comparison logic below can cope
1133 * with some cases of non-identical row types.
1134 */
1135 if (OidIsValid(scalar_type) && scalar_type != RECORDOID)
1136 array_type = get_array_type(scalar_type);
1137 else
1138 array_type = InvalidOid;
1139 if (array_type != InvalidOid)
1140 {
1141 /*
1142 * OK: coerce all the right-hand non-Var inputs to the common type
1143 * and build an ArrayExpr for them.
1144 */
1145 List *aexprs;
1146 ArrayExpr *newa;
1147
1148 aexprs = NIL;
1149 foreach(l, rnonvars)
1150 {
1151 Node *rexpr = (Node *) lfirst(l);
1152
1153 rexpr = coerce_to_common_type(pstate, rexpr,
1154 scalar_type,
1155 "IN");
1156 aexprs = lappend(aexprs, rexpr);
1157 }
1158 newa = makeNode(ArrayExpr);
1159 newa->array_typeid = array_type;
1160 /* array_collid will be set by parse_collate.c */
1161 newa->element_typeid = scalar_type;
1162 newa->elements = aexprs;
1163 newa->multidims = false;
1164 newa->location = -1;
1165
1166 result = (Node *) make_scalar_array_op(pstate,
1167 a->name,
1168 useOr,
1169 lexpr,
1170 (Node *) newa,
1171 a->location);
1172
1173 /* Consider only the Vars (if any) in the loop below */
1174 rexprs = rvars;
1175 }
1176 }
1177
1178 /*
1179 * Must do it the hard way, ie, with a boolean expression tree.
1180 */
1181 foreach(l, rexprs)
1182 {
1183 Node *rexpr = (Node *) lfirst(l);
1184 Node *cmp;
1185
1186 if (IsA(lexpr, RowExpr) &&
1187 IsA(rexpr, RowExpr))
1188 {
1189 /* ROW() op ROW() is handled specially */
1190 cmp = make_row_comparison_op(pstate,
1191 a->name,
1192 copyObject(((RowExpr *) lexpr)->args),
1193 ((RowExpr *) rexpr)->args,
1194 a->location);
1195 }
1196 else
1197 {
1198 /* Ordinary scalar operator */
1199 cmp = (Node *) make_op(pstate,
1200 a->name,
1201 copyObject(lexpr),
1202 rexpr,
1203 pstate->p_last_srf,
1204 a->location);
1205 }
1206
1207 cmp = coerce_to_boolean(pstate, cmp, "IN");
1208 if (result == NULL)
1209 result = cmp;
1210 else
1211 result = (Node *) makeBoolExpr(useOr ? OR_EXPR : AND_EXPR,
1212 list_make2(result, cmp),
1213 a->location);
1214 }
1215
1216 return result;
1217 }
1218
1219 static Node *
transformAExprBetween(ParseState * pstate,A_Expr * a)1220 transformAExprBetween(ParseState *pstate, A_Expr *a)
1221 {
1222 Node *aexpr;
1223 Node *bexpr;
1224 Node *cexpr;
1225 Node *result;
1226 Node *sub1;
1227 Node *sub2;
1228 List *args;
1229
1230 /* Deconstruct A_Expr into three subexprs */
1231 aexpr = a->lexpr;
1232 args = castNode(List, a->rexpr);
1233 Assert(list_length(args) == 2);
1234 bexpr = (Node *) linitial(args);
1235 cexpr = (Node *) lsecond(args);
1236
1237 /*
1238 * Build the equivalent comparison expression. Make copies of
1239 * multiply-referenced subexpressions for safety. (XXX this is really
1240 * wrong since it results in multiple runtime evaluations of what may be
1241 * volatile expressions ...)
1242 *
1243 * Ideally we would not use hard-wired operators here but instead use
1244 * opclasses. However, mixed data types and other issues make this
1245 * difficult:
1246 * http://archives.postgresql.org/pgsql-hackers/2008-08/msg01142.php
1247 */
1248 switch (a->kind)
1249 {
1250 case AEXPR_BETWEEN:
1251 args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
1252 aexpr, bexpr,
1253 a->location),
1254 makeSimpleA_Expr(AEXPR_OP, "<=",
1255 copyObject(aexpr), cexpr,
1256 a->location));
1257 result = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
1258 break;
1259 case AEXPR_NOT_BETWEEN:
1260 args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
1261 aexpr, bexpr,
1262 a->location),
1263 makeSimpleA_Expr(AEXPR_OP, ">",
1264 copyObject(aexpr), cexpr,
1265 a->location));
1266 result = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
1267 break;
1268 case AEXPR_BETWEEN_SYM:
1269 args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
1270 aexpr, bexpr,
1271 a->location),
1272 makeSimpleA_Expr(AEXPR_OP, "<=",
1273 copyObject(aexpr), cexpr,
1274 a->location));
1275 sub1 = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
1276 args = list_make2(makeSimpleA_Expr(AEXPR_OP, ">=",
1277 copyObject(aexpr), copyObject(cexpr),
1278 a->location),
1279 makeSimpleA_Expr(AEXPR_OP, "<=",
1280 copyObject(aexpr), copyObject(bexpr),
1281 a->location));
1282 sub2 = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
1283 args = list_make2(sub1, sub2);
1284 result = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
1285 break;
1286 case AEXPR_NOT_BETWEEN_SYM:
1287 args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
1288 aexpr, bexpr,
1289 a->location),
1290 makeSimpleA_Expr(AEXPR_OP, ">",
1291 copyObject(aexpr), cexpr,
1292 a->location));
1293 sub1 = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
1294 args = list_make2(makeSimpleA_Expr(AEXPR_OP, "<",
1295 copyObject(aexpr), copyObject(cexpr),
1296 a->location),
1297 makeSimpleA_Expr(AEXPR_OP, ">",
1298 copyObject(aexpr), copyObject(bexpr),
1299 a->location));
1300 sub2 = (Node *) makeBoolExpr(OR_EXPR, args, a->location);
1301 args = list_make2(sub1, sub2);
1302 result = (Node *) makeBoolExpr(AND_EXPR, args, a->location);
1303 break;
1304 default:
1305 elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
1306 result = NULL; /* keep compiler quiet */
1307 break;
1308 }
1309
1310 return transformExprRecurse(pstate, result);
1311 }
1312
1313 static Node *
transformBoolExpr(ParseState * pstate,BoolExpr * a)1314 transformBoolExpr(ParseState *pstate, BoolExpr *a)
1315 {
1316 List *args = NIL;
1317 const char *opname;
1318 ListCell *lc;
1319
1320 switch (a->boolop)
1321 {
1322 case AND_EXPR:
1323 opname = "AND";
1324 break;
1325 case OR_EXPR:
1326 opname = "OR";
1327 break;
1328 case NOT_EXPR:
1329 opname = "NOT";
1330 break;
1331 default:
1332 elog(ERROR, "unrecognized boolop: %d", (int) a->boolop);
1333 opname = NULL; /* keep compiler quiet */
1334 break;
1335 }
1336
1337 foreach(lc, a->args)
1338 {
1339 Node *arg = (Node *) lfirst(lc);
1340
1341 arg = transformExprRecurse(pstate, arg);
1342 arg = coerce_to_boolean(pstate, arg, opname);
1343 args = lappend(args, arg);
1344 }
1345
1346 return (Node *) makeBoolExpr(a->boolop, args, a->location);
1347 }
1348
1349 static Node *
transformFuncCall(ParseState * pstate,FuncCall * fn)1350 transformFuncCall(ParseState *pstate, FuncCall *fn)
1351 {
1352 Node *last_srf = pstate->p_last_srf;
1353 List *targs;
1354 ListCell *args;
1355
1356 /* Transform the list of arguments ... */
1357 targs = NIL;
1358 foreach(args, fn->args)
1359 {
1360 targs = lappend(targs, transformExprRecurse(pstate,
1361 (Node *) lfirst(args)));
1362 }
1363
1364 /*
1365 * When WITHIN GROUP is used, we treat its ORDER BY expressions as
1366 * additional arguments to the function, for purposes of function lookup
1367 * and argument type coercion. So, transform each such expression and add
1368 * them to the targs list. We don't explicitly mark where each argument
1369 * came from, but ParseFuncOrColumn can tell what's what by reference to
1370 * list_length(fn->agg_order).
1371 */
1372 if (fn->agg_within_group)
1373 {
1374 Assert(fn->agg_order != NIL);
1375 foreach(args, fn->agg_order)
1376 {
1377 SortBy *arg = (SortBy *) lfirst(args);
1378
1379 targs = lappend(targs, transformExpr(pstate, arg->node,
1380 EXPR_KIND_ORDER_BY));
1381 }
1382 }
1383
1384 /* ... and hand off to ParseFuncOrColumn */
1385 return ParseFuncOrColumn(pstate,
1386 fn->funcname,
1387 targs,
1388 last_srf,
1389 fn,
1390 false,
1391 fn->location);
1392 }
1393
1394 static Node *
transformMultiAssignRef(ParseState * pstate,MultiAssignRef * maref)1395 transformMultiAssignRef(ParseState *pstate, MultiAssignRef *maref)
1396 {
1397 SubLink *sublink;
1398 RowExpr *rexpr;
1399 Query *qtree;
1400 TargetEntry *tle;
1401
1402 /* We should only see this in first-stage processing of UPDATE tlists */
1403 Assert(pstate->p_expr_kind == EXPR_KIND_UPDATE_SOURCE);
1404
1405 /* We only need to transform the source if this is the first column */
1406 if (maref->colno == 1)
1407 {
1408 /*
1409 * For now, we only allow EXPR SubLinks and RowExprs as the source of
1410 * an UPDATE multiassignment. This is sufficient to cover interesting
1411 * cases; at worst, someone would have to write (SELECT * FROM expr)
1412 * to expand a composite-returning expression of another form.
1413 */
1414 if (IsA(maref->source, SubLink) &&
1415 ((SubLink *) maref->source)->subLinkType == EXPR_SUBLINK)
1416 {
1417 /* Relabel it as a MULTIEXPR_SUBLINK */
1418 sublink = (SubLink *) maref->source;
1419 sublink->subLinkType = MULTIEXPR_SUBLINK;
1420 /* And transform it */
1421 sublink = (SubLink *) transformExprRecurse(pstate,
1422 (Node *) sublink);
1423
1424 qtree = castNode(Query, sublink->subselect);
1425
1426 /* Check subquery returns required number of columns */
1427 if (count_nonjunk_tlist_entries(qtree->targetList) != maref->ncolumns)
1428 ereport(ERROR,
1429 (errcode(ERRCODE_SYNTAX_ERROR),
1430 errmsg("number of columns does not match number of values"),
1431 parser_errposition(pstate, sublink->location)));
1432
1433 /*
1434 * Build a resjunk tlist item containing the MULTIEXPR SubLink,
1435 * and add it to pstate->p_multiassign_exprs, whence it will later
1436 * get appended to the completed targetlist. We needn't worry
1437 * about selecting a resno for it; transformUpdateStmt will do
1438 * that.
1439 */
1440 tle = makeTargetEntry((Expr *) sublink, 0, NULL, true);
1441 pstate->p_multiassign_exprs = lappend(pstate->p_multiassign_exprs,
1442 tle);
1443
1444 /*
1445 * Assign a unique-within-this-targetlist ID to the MULTIEXPR
1446 * SubLink. We can just use its position in the
1447 * p_multiassign_exprs list.
1448 */
1449 sublink->subLinkId = list_length(pstate->p_multiassign_exprs);
1450 }
1451 else if (IsA(maref->source, RowExpr))
1452 {
1453 /* Transform the RowExpr, allowing SetToDefault items */
1454 rexpr = (RowExpr *) transformRowExpr(pstate,
1455 (RowExpr *) maref->source,
1456 true);
1457
1458 /* Check it returns required number of columns */
1459 if (list_length(rexpr->args) != maref->ncolumns)
1460 ereport(ERROR,
1461 (errcode(ERRCODE_SYNTAX_ERROR),
1462 errmsg("number of columns does not match number of values"),
1463 parser_errposition(pstate, rexpr->location)));
1464
1465 /*
1466 * Temporarily append it to p_multiassign_exprs, so we can get it
1467 * back when we come back here for additional columns.
1468 */
1469 tle = makeTargetEntry((Expr *) rexpr, 0, NULL, true);
1470 pstate->p_multiassign_exprs = lappend(pstate->p_multiassign_exprs,
1471 tle);
1472 }
1473 else
1474 ereport(ERROR,
1475 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1476 errmsg("source for a multiple-column UPDATE item must be a sub-SELECT or ROW() expression"),
1477 parser_errposition(pstate, exprLocation(maref->source))));
1478 }
1479 else
1480 {
1481 /*
1482 * Second or later column in a multiassignment. Re-fetch the
1483 * transformed SubLink or RowExpr, which we assume is still the last
1484 * entry in p_multiassign_exprs.
1485 */
1486 Assert(pstate->p_multiassign_exprs != NIL);
1487 tle = (TargetEntry *) llast(pstate->p_multiassign_exprs);
1488 }
1489
1490 /*
1491 * Emit the appropriate output expression for the current column
1492 */
1493 if (IsA(tle->expr, SubLink))
1494 {
1495 Param *param;
1496
1497 sublink = (SubLink *) tle->expr;
1498 Assert(sublink->subLinkType == MULTIEXPR_SUBLINK);
1499 qtree = castNode(Query, sublink->subselect);
1500
1501 /* Build a Param representing the current subquery output column */
1502 tle = (TargetEntry *) list_nth(qtree->targetList, maref->colno - 1);
1503 Assert(!tle->resjunk);
1504
1505 param = makeNode(Param);
1506 param->paramkind = PARAM_MULTIEXPR;
1507 param->paramid = (sublink->subLinkId << 16) | maref->colno;
1508 param->paramtype = exprType((Node *) tle->expr);
1509 param->paramtypmod = exprTypmod((Node *) tle->expr);
1510 param->paramcollid = exprCollation((Node *) tle->expr);
1511 param->location = exprLocation((Node *) tle->expr);
1512
1513 return (Node *) param;
1514 }
1515
1516 if (IsA(tle->expr, RowExpr))
1517 {
1518 Node *result;
1519
1520 rexpr = (RowExpr *) tle->expr;
1521
1522 /* Just extract and return the next element of the RowExpr */
1523 result = (Node *) list_nth(rexpr->args, maref->colno - 1);
1524
1525 /*
1526 * If we're at the last column, delete the RowExpr from
1527 * p_multiassign_exprs; we don't need it anymore, and don't want it in
1528 * the finished UPDATE tlist. We assume this is still the last entry
1529 * in p_multiassign_exprs.
1530 */
1531 if (maref->colno == maref->ncolumns)
1532 pstate->p_multiassign_exprs =
1533 list_delete_last(pstate->p_multiassign_exprs);
1534
1535 return result;
1536 }
1537
1538 elog(ERROR, "unexpected expr type in multiassign list");
1539 return NULL; /* keep compiler quiet */
1540 }
1541
1542 static Node *
transformCaseExpr(ParseState * pstate,CaseExpr * c)1543 transformCaseExpr(ParseState *pstate, CaseExpr *c)
1544 {
1545 CaseExpr *newc = makeNode(CaseExpr);
1546 Node *last_srf = pstate->p_last_srf;
1547 Node *arg;
1548 CaseTestExpr *placeholder;
1549 List *newargs;
1550 List *resultexprs;
1551 ListCell *l;
1552 Node *defresult;
1553 Oid ptype;
1554
1555 /* transform the test expression, if any */
1556 arg = transformExprRecurse(pstate, (Node *) c->arg);
1557
1558 /* generate placeholder for test expression */
1559 if (arg)
1560 {
1561 /*
1562 * If test expression is an untyped literal, force it to text. We have
1563 * to do something now because we won't be able to do this coercion on
1564 * the placeholder. This is not as flexible as what was done in 7.4
1565 * and before, but it's good enough to handle the sort of silly coding
1566 * commonly seen.
1567 */
1568 if (exprType(arg) == UNKNOWNOID)
1569 arg = coerce_to_common_type(pstate, arg, TEXTOID, "CASE");
1570
1571 /*
1572 * Run collation assignment on the test expression so that we know
1573 * what collation to mark the placeholder with. In principle we could
1574 * leave it to parse_collate.c to do that later, but propagating the
1575 * result to the CaseTestExpr would be unnecessarily complicated.
1576 */
1577 assign_expr_collations(pstate, arg);
1578
1579 placeholder = makeNode(CaseTestExpr);
1580 placeholder->typeId = exprType(arg);
1581 placeholder->typeMod = exprTypmod(arg);
1582 placeholder->collation = exprCollation(arg);
1583 }
1584 else
1585 placeholder = NULL;
1586
1587 newc->arg = (Expr *) arg;
1588
1589 /* transform the list of arguments */
1590 newargs = NIL;
1591 resultexprs = NIL;
1592 foreach(l, c->args)
1593 {
1594 CaseWhen *w = lfirst_node(CaseWhen, l);
1595 CaseWhen *neww = makeNode(CaseWhen);
1596 Node *warg;
1597
1598 warg = (Node *) w->expr;
1599 if (placeholder)
1600 {
1601 /* shorthand form was specified, so expand... */
1602 warg = (Node *) makeSimpleA_Expr(AEXPR_OP, "=",
1603 (Node *) placeholder,
1604 warg,
1605 w->location);
1606 }
1607 neww->expr = (Expr *) transformExprRecurse(pstate, warg);
1608
1609 neww->expr = (Expr *) coerce_to_boolean(pstate,
1610 (Node *) neww->expr,
1611 "CASE/WHEN");
1612
1613 warg = (Node *) w->result;
1614 neww->result = (Expr *) transformExprRecurse(pstate, warg);
1615 neww->location = w->location;
1616
1617 newargs = lappend(newargs, neww);
1618 resultexprs = lappend(resultexprs, neww->result);
1619 }
1620
1621 newc->args = newargs;
1622
1623 /* transform the default clause */
1624 defresult = (Node *) c->defresult;
1625 if (defresult == NULL)
1626 {
1627 A_Const *n = makeNode(A_Const);
1628
1629 n->val.type = T_Null;
1630 n->location = -1;
1631 defresult = (Node *) n;
1632 }
1633 newc->defresult = (Expr *) transformExprRecurse(pstate, defresult);
1634
1635 /*
1636 * Note: default result is considered the most significant type in
1637 * determining preferred type. This is how the code worked before, but it
1638 * seems a little bogus to me --- tgl
1639 */
1640 resultexprs = lcons(newc->defresult, resultexprs);
1641
1642 ptype = select_common_type(pstate, resultexprs, "CASE", NULL);
1643 Assert(OidIsValid(ptype));
1644 newc->casetype = ptype;
1645 /* casecollid will be set by parse_collate.c */
1646
1647 /* Convert default result clause, if necessary */
1648 newc->defresult = (Expr *)
1649 coerce_to_common_type(pstate,
1650 (Node *) newc->defresult,
1651 ptype,
1652 "CASE/ELSE");
1653
1654 /* Convert when-clause results, if necessary */
1655 foreach(l, newc->args)
1656 {
1657 CaseWhen *w = (CaseWhen *) lfirst(l);
1658
1659 w->result = (Expr *)
1660 coerce_to_common_type(pstate,
1661 (Node *) w->result,
1662 ptype,
1663 "CASE/WHEN");
1664 }
1665
1666 /* if any subexpression contained a SRF, complain */
1667 if (pstate->p_last_srf != last_srf)
1668 ereport(ERROR,
1669 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1670 /* translator: %s is name of a SQL construct, eg GROUP BY */
1671 errmsg("set-returning functions are not allowed in %s",
1672 "CASE"),
1673 errhint("You might be able to move the set-returning function into a LATERAL FROM item."),
1674 parser_errposition(pstate,
1675 exprLocation(pstate->p_last_srf))));
1676
1677 newc->location = c->location;
1678
1679 return (Node *) newc;
1680 }
1681
1682 static Node *
transformSubLink(ParseState * pstate,SubLink * sublink)1683 transformSubLink(ParseState *pstate, SubLink *sublink)
1684 {
1685 Node *result = (Node *) sublink;
1686 Query *qtree;
1687 const char *err;
1688
1689 /*
1690 * Check to see if the sublink is in an invalid place within the query. We
1691 * allow sublinks everywhere in SELECT/INSERT/UPDATE/DELETE, but generally
1692 * not in utility statements.
1693 */
1694 err = NULL;
1695 switch (pstate->p_expr_kind)
1696 {
1697 case EXPR_KIND_NONE:
1698 Assert(false); /* can't happen */
1699 break;
1700 case EXPR_KIND_OTHER:
1701 /* Accept sublink here; caller must throw error if wanted */
1702 break;
1703 case EXPR_KIND_JOIN_ON:
1704 case EXPR_KIND_JOIN_USING:
1705 case EXPR_KIND_FROM_SUBSELECT:
1706 case EXPR_KIND_FROM_FUNCTION:
1707 case EXPR_KIND_WHERE:
1708 case EXPR_KIND_POLICY:
1709 case EXPR_KIND_HAVING:
1710 case EXPR_KIND_FILTER:
1711 case EXPR_KIND_WINDOW_PARTITION:
1712 case EXPR_KIND_WINDOW_ORDER:
1713 case EXPR_KIND_WINDOW_FRAME_RANGE:
1714 case EXPR_KIND_WINDOW_FRAME_ROWS:
1715 case EXPR_KIND_WINDOW_FRAME_GROUPS:
1716 case EXPR_KIND_SELECT_TARGET:
1717 case EXPR_KIND_INSERT_TARGET:
1718 case EXPR_KIND_UPDATE_SOURCE:
1719 case EXPR_KIND_UPDATE_TARGET:
1720 case EXPR_KIND_GROUP_BY:
1721 case EXPR_KIND_ORDER_BY:
1722 case EXPR_KIND_DISTINCT_ON:
1723 case EXPR_KIND_LIMIT:
1724 case EXPR_KIND_OFFSET:
1725 case EXPR_KIND_RETURNING:
1726 case EXPR_KIND_VALUES:
1727 case EXPR_KIND_VALUES_SINGLE:
1728 case EXPR_KIND_CYCLE_MARK:
1729 /* okay */
1730 break;
1731 case EXPR_KIND_CHECK_CONSTRAINT:
1732 case EXPR_KIND_DOMAIN_CHECK:
1733 err = _("cannot use subquery in check constraint");
1734 break;
1735 case EXPR_KIND_COLUMN_DEFAULT:
1736 case EXPR_KIND_FUNCTION_DEFAULT:
1737 err = _("cannot use subquery in DEFAULT expression");
1738 break;
1739 case EXPR_KIND_INDEX_EXPRESSION:
1740 err = _("cannot use subquery in index expression");
1741 break;
1742 case EXPR_KIND_INDEX_PREDICATE:
1743 err = _("cannot use subquery in index predicate");
1744 break;
1745 case EXPR_KIND_STATS_EXPRESSION:
1746 err = _("cannot use subquery in statistics expression");
1747 break;
1748 case EXPR_KIND_ALTER_COL_TRANSFORM:
1749 err = _("cannot use subquery in transform expression");
1750 break;
1751 case EXPR_KIND_EXECUTE_PARAMETER:
1752 err = _("cannot use subquery in EXECUTE parameter");
1753 break;
1754 case EXPR_KIND_TRIGGER_WHEN:
1755 err = _("cannot use subquery in trigger WHEN condition");
1756 break;
1757 case EXPR_KIND_PARTITION_BOUND:
1758 err = _("cannot use subquery in partition bound");
1759 break;
1760 case EXPR_KIND_PARTITION_EXPRESSION:
1761 err = _("cannot use subquery in partition key expression");
1762 break;
1763 case EXPR_KIND_CALL_ARGUMENT:
1764 err = _("cannot use subquery in CALL argument");
1765 break;
1766 case EXPR_KIND_COPY_WHERE:
1767 err = _("cannot use subquery in COPY FROM WHERE condition");
1768 break;
1769 case EXPR_KIND_GENERATED_COLUMN:
1770 err = _("cannot use subquery in column generation expression");
1771 break;
1772
1773 /*
1774 * There is intentionally no default: case here, so that the
1775 * compiler will warn if we add a new ParseExprKind without
1776 * extending this switch. If we do see an unrecognized value at
1777 * runtime, the behavior will be the same as for EXPR_KIND_OTHER,
1778 * which is sane anyway.
1779 */
1780 }
1781 if (err)
1782 ereport(ERROR,
1783 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1784 errmsg_internal("%s", err),
1785 parser_errposition(pstate, sublink->location)));
1786
1787 pstate->p_hasSubLinks = true;
1788
1789 /*
1790 * OK, let's transform the sub-SELECT.
1791 */
1792 qtree = parse_sub_analyze(sublink->subselect, pstate, NULL, false, true);
1793
1794 /*
1795 * Check that we got a SELECT. Anything else should be impossible given
1796 * restrictions of the grammar, but check anyway.
1797 */
1798 if (!IsA(qtree, Query) ||
1799 qtree->commandType != CMD_SELECT)
1800 elog(ERROR, "unexpected non-SELECT command in SubLink");
1801
1802 sublink->subselect = (Node *) qtree;
1803
1804 if (sublink->subLinkType == EXISTS_SUBLINK)
1805 {
1806 /*
1807 * EXISTS needs no test expression or combining operator. These fields
1808 * should be null already, but make sure.
1809 */
1810 sublink->testexpr = NULL;
1811 sublink->operName = NIL;
1812 }
1813 else if (sublink->subLinkType == EXPR_SUBLINK ||
1814 sublink->subLinkType == ARRAY_SUBLINK)
1815 {
1816 /*
1817 * Make sure the subselect delivers a single column (ignoring resjunk
1818 * targets).
1819 */
1820 if (count_nonjunk_tlist_entries(qtree->targetList) != 1)
1821 ereport(ERROR,
1822 (errcode(ERRCODE_SYNTAX_ERROR),
1823 errmsg("subquery must return only one column"),
1824 parser_errposition(pstate, sublink->location)));
1825
1826 /*
1827 * EXPR and ARRAY need no test expression or combining operator. These
1828 * fields should be null already, but make sure.
1829 */
1830 sublink->testexpr = NULL;
1831 sublink->operName = NIL;
1832 }
1833 else if (sublink->subLinkType == MULTIEXPR_SUBLINK)
1834 {
1835 /* Same as EXPR case, except no restriction on number of columns */
1836 sublink->testexpr = NULL;
1837 sublink->operName = NIL;
1838 }
1839 else
1840 {
1841 /* ALL, ANY, or ROWCOMPARE: generate row-comparing expression */
1842 Node *lefthand;
1843 List *left_list;
1844 List *right_list;
1845 ListCell *l;
1846
1847 /*
1848 * If the source was "x IN (select)", convert to "x = ANY (select)".
1849 */
1850 if (sublink->operName == NIL)
1851 sublink->operName = list_make1(makeString("="));
1852
1853 /*
1854 * Transform lefthand expression, and convert to a list
1855 */
1856 lefthand = transformExprRecurse(pstate, sublink->testexpr);
1857 if (lefthand && IsA(lefthand, RowExpr))
1858 left_list = ((RowExpr *) lefthand)->args;
1859 else
1860 left_list = list_make1(lefthand);
1861
1862 /*
1863 * Build a list of PARAM_SUBLINK nodes representing the output columns
1864 * of the subquery.
1865 */
1866 right_list = NIL;
1867 foreach(l, qtree->targetList)
1868 {
1869 TargetEntry *tent = (TargetEntry *) lfirst(l);
1870 Param *param;
1871
1872 if (tent->resjunk)
1873 continue;
1874
1875 param = makeNode(Param);
1876 param->paramkind = PARAM_SUBLINK;
1877 param->paramid = tent->resno;
1878 param->paramtype = exprType((Node *) tent->expr);
1879 param->paramtypmod = exprTypmod((Node *) tent->expr);
1880 param->paramcollid = exprCollation((Node *) tent->expr);
1881 param->location = -1;
1882
1883 right_list = lappend(right_list, param);
1884 }
1885
1886 /*
1887 * We could rely on make_row_comparison_op to complain if the list
1888 * lengths differ, but we prefer to generate a more specific error
1889 * message.
1890 */
1891 if (list_length(left_list) < list_length(right_list))
1892 ereport(ERROR,
1893 (errcode(ERRCODE_SYNTAX_ERROR),
1894 errmsg("subquery has too many columns"),
1895 parser_errposition(pstate, sublink->location)));
1896 if (list_length(left_list) > list_length(right_list))
1897 ereport(ERROR,
1898 (errcode(ERRCODE_SYNTAX_ERROR),
1899 errmsg("subquery has too few columns"),
1900 parser_errposition(pstate, sublink->location)));
1901
1902 /*
1903 * Identify the combining operator(s) and generate a suitable
1904 * row-comparison expression.
1905 */
1906 sublink->testexpr = make_row_comparison_op(pstate,
1907 sublink->operName,
1908 left_list,
1909 right_list,
1910 sublink->location);
1911 }
1912
1913 return result;
1914 }
1915
1916 /*
1917 * transformArrayExpr
1918 *
1919 * If the caller specifies the target type, the resulting array will
1920 * be of exactly that type. Otherwise we try to infer a common type
1921 * for the elements using select_common_type().
1922 */
1923 static Node *
transformArrayExpr(ParseState * pstate,A_ArrayExpr * a,Oid array_type,Oid element_type,int32 typmod)1924 transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
1925 Oid array_type, Oid element_type, int32 typmod)
1926 {
1927 ArrayExpr *newa = makeNode(ArrayExpr);
1928 List *newelems = NIL;
1929 List *newcoercedelems = NIL;
1930 ListCell *element;
1931 Oid coerce_type;
1932 bool coerce_hard;
1933
1934 /*
1935 * Transform the element expressions
1936 *
1937 * Assume that the array is one-dimensional unless we find an array-type
1938 * element expression.
1939 */
1940 newa->multidims = false;
1941 foreach(element, a->elements)
1942 {
1943 Node *e = (Node *) lfirst(element);
1944 Node *newe;
1945
1946 /*
1947 * If an element is itself an A_ArrayExpr, recurse directly so that we
1948 * can pass down any target type we were given.
1949 */
1950 if (IsA(e, A_ArrayExpr))
1951 {
1952 newe = transformArrayExpr(pstate,
1953 (A_ArrayExpr *) e,
1954 array_type,
1955 element_type,
1956 typmod);
1957 /* we certainly have an array here */
1958 Assert(array_type == InvalidOid || array_type == exprType(newe));
1959 newa->multidims = true;
1960 }
1961 else
1962 {
1963 newe = transformExprRecurse(pstate, e);
1964
1965 /*
1966 * Check for sub-array expressions, if we haven't already found
1967 * one.
1968 */
1969 if (!newa->multidims && type_is_array(exprType(newe)))
1970 newa->multidims = true;
1971 }
1972
1973 newelems = lappend(newelems, newe);
1974 }
1975
1976 /*
1977 * Select a target type for the elements.
1978 *
1979 * If we haven't been given a target array type, we must try to deduce a
1980 * common type based on the types of the individual elements present.
1981 */
1982 if (OidIsValid(array_type))
1983 {
1984 /* Caller must ensure array_type matches element_type */
1985 Assert(OidIsValid(element_type));
1986 coerce_type = (newa->multidims ? array_type : element_type);
1987 coerce_hard = true;
1988 }
1989 else
1990 {
1991 /* Can't handle an empty array without a target type */
1992 if (newelems == NIL)
1993 ereport(ERROR,
1994 (errcode(ERRCODE_INDETERMINATE_DATATYPE),
1995 errmsg("cannot determine type of empty array"),
1996 errhint("Explicitly cast to the desired type, "
1997 "for example ARRAY[]::integer[]."),
1998 parser_errposition(pstate, a->location)));
1999
2000 /* Select a common type for the elements */
2001 coerce_type = select_common_type(pstate, newelems, "ARRAY", NULL);
2002
2003 if (newa->multidims)
2004 {
2005 array_type = coerce_type;
2006 element_type = get_element_type(array_type);
2007 if (!OidIsValid(element_type))
2008 ereport(ERROR,
2009 (errcode(ERRCODE_UNDEFINED_OBJECT),
2010 errmsg("could not find element type for data type %s",
2011 format_type_be(array_type)),
2012 parser_errposition(pstate, a->location)));
2013 }
2014 else
2015 {
2016 element_type = coerce_type;
2017 array_type = get_array_type(element_type);
2018 if (!OidIsValid(array_type))
2019 ereport(ERROR,
2020 (errcode(ERRCODE_UNDEFINED_OBJECT),
2021 errmsg("could not find array type for data type %s",
2022 format_type_be(element_type)),
2023 parser_errposition(pstate, a->location)));
2024 }
2025 coerce_hard = false;
2026 }
2027
2028 /*
2029 * Coerce elements to target type
2030 *
2031 * If the array has been explicitly cast, then the elements are in turn
2032 * explicitly coerced.
2033 *
2034 * If the array's type was merely derived from the common type of its
2035 * elements, then the elements are implicitly coerced to the common type.
2036 * This is consistent with other uses of select_common_type().
2037 */
2038 foreach(element, newelems)
2039 {
2040 Node *e = (Node *) lfirst(element);
2041 Node *newe;
2042
2043 if (coerce_hard)
2044 {
2045 newe = coerce_to_target_type(pstate, e,
2046 exprType(e),
2047 coerce_type,
2048 typmod,
2049 COERCION_EXPLICIT,
2050 COERCE_EXPLICIT_CAST,
2051 -1);
2052 if (newe == NULL)
2053 ereport(ERROR,
2054 (errcode(ERRCODE_CANNOT_COERCE),
2055 errmsg("cannot cast type %s to %s",
2056 format_type_be(exprType(e)),
2057 format_type_be(coerce_type)),
2058 parser_errposition(pstate, exprLocation(e))));
2059 }
2060 else
2061 newe = coerce_to_common_type(pstate, e,
2062 coerce_type,
2063 "ARRAY");
2064 newcoercedelems = lappend(newcoercedelems, newe);
2065 }
2066
2067 newa->array_typeid = array_type;
2068 /* array_collid will be set by parse_collate.c */
2069 newa->element_typeid = element_type;
2070 newa->elements = newcoercedelems;
2071 newa->location = a->location;
2072
2073 return (Node *) newa;
2074 }
2075
2076 static Node *
transformRowExpr(ParseState * pstate,RowExpr * r,bool allowDefault)2077 transformRowExpr(ParseState *pstate, RowExpr *r, bool allowDefault)
2078 {
2079 RowExpr *newr;
2080 char fname[16];
2081 int fnum;
2082
2083 newr = makeNode(RowExpr);
2084
2085 /* Transform the field expressions */
2086 newr->args = transformExpressionList(pstate, r->args,
2087 pstate->p_expr_kind, allowDefault);
2088
2089 /* Barring later casting, we consider the type RECORD */
2090 newr->row_typeid = RECORDOID;
2091 newr->row_format = COERCE_IMPLICIT_CAST;
2092
2093 /* ROW() has anonymous columns, so invent some field names */
2094 newr->colnames = NIL;
2095 for (fnum = 1; fnum <= list_length(newr->args); fnum++)
2096 {
2097 snprintf(fname, sizeof(fname), "f%d", fnum);
2098 newr->colnames = lappend(newr->colnames, makeString(pstrdup(fname)));
2099 }
2100
2101 newr->location = r->location;
2102
2103 return (Node *) newr;
2104 }
2105
2106 static Node *
transformCoalesceExpr(ParseState * pstate,CoalesceExpr * c)2107 transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
2108 {
2109 CoalesceExpr *newc = makeNode(CoalesceExpr);
2110 Node *last_srf = pstate->p_last_srf;
2111 List *newargs = NIL;
2112 List *newcoercedargs = NIL;
2113 ListCell *args;
2114
2115 foreach(args, c->args)
2116 {
2117 Node *e = (Node *) lfirst(args);
2118 Node *newe;
2119
2120 newe = transformExprRecurse(pstate, e);
2121 newargs = lappend(newargs, newe);
2122 }
2123
2124 newc->coalescetype = select_common_type(pstate, newargs, "COALESCE", NULL);
2125 /* coalescecollid will be set by parse_collate.c */
2126
2127 /* Convert arguments if necessary */
2128 foreach(args, newargs)
2129 {
2130 Node *e = (Node *) lfirst(args);
2131 Node *newe;
2132
2133 newe = coerce_to_common_type(pstate, e,
2134 newc->coalescetype,
2135 "COALESCE");
2136 newcoercedargs = lappend(newcoercedargs, newe);
2137 }
2138
2139 /* if any subexpression contained a SRF, complain */
2140 if (pstate->p_last_srf != last_srf)
2141 ereport(ERROR,
2142 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2143 /* translator: %s is name of a SQL construct, eg GROUP BY */
2144 errmsg("set-returning functions are not allowed in %s",
2145 "COALESCE"),
2146 errhint("You might be able to move the set-returning function into a LATERAL FROM item."),
2147 parser_errposition(pstate,
2148 exprLocation(pstate->p_last_srf))));
2149
2150 newc->args = newcoercedargs;
2151 newc->location = c->location;
2152 return (Node *) newc;
2153 }
2154
2155 static Node *
transformMinMaxExpr(ParseState * pstate,MinMaxExpr * m)2156 transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
2157 {
2158 MinMaxExpr *newm = makeNode(MinMaxExpr);
2159 List *newargs = NIL;
2160 List *newcoercedargs = NIL;
2161 const char *funcname = (m->op == IS_GREATEST) ? "GREATEST" : "LEAST";
2162 ListCell *args;
2163
2164 newm->op = m->op;
2165 foreach(args, m->args)
2166 {
2167 Node *e = (Node *) lfirst(args);
2168 Node *newe;
2169
2170 newe = transformExprRecurse(pstate, e);
2171 newargs = lappend(newargs, newe);
2172 }
2173
2174 newm->minmaxtype = select_common_type(pstate, newargs, funcname, NULL);
2175 /* minmaxcollid and inputcollid will be set by parse_collate.c */
2176
2177 /* Convert arguments if necessary */
2178 foreach(args, newargs)
2179 {
2180 Node *e = (Node *) lfirst(args);
2181 Node *newe;
2182
2183 newe = coerce_to_common_type(pstate, e,
2184 newm->minmaxtype,
2185 funcname);
2186 newcoercedargs = lappend(newcoercedargs, newe);
2187 }
2188
2189 newm->args = newcoercedargs;
2190 newm->location = m->location;
2191 return (Node *) newm;
2192 }
2193
2194 static Node *
transformSQLValueFunction(ParseState * pstate,SQLValueFunction * svf)2195 transformSQLValueFunction(ParseState *pstate, SQLValueFunction *svf)
2196 {
2197 /*
2198 * All we need to do is insert the correct result type and (where needed)
2199 * validate the typmod, so we just modify the node in-place.
2200 */
2201 switch (svf->op)
2202 {
2203 case SVFOP_CURRENT_DATE:
2204 svf->type = DATEOID;
2205 break;
2206 case SVFOP_CURRENT_TIME:
2207 svf->type = TIMETZOID;
2208 break;
2209 case SVFOP_CURRENT_TIME_N:
2210 svf->type = TIMETZOID;
2211 svf->typmod = anytime_typmod_check(true, svf->typmod);
2212 break;
2213 case SVFOP_CURRENT_TIMESTAMP:
2214 svf->type = TIMESTAMPTZOID;
2215 break;
2216 case SVFOP_CURRENT_TIMESTAMP_N:
2217 svf->type = TIMESTAMPTZOID;
2218 svf->typmod = anytimestamp_typmod_check(true, svf->typmod);
2219 break;
2220 case SVFOP_LOCALTIME:
2221 svf->type = TIMEOID;
2222 break;
2223 case SVFOP_LOCALTIME_N:
2224 svf->type = TIMEOID;
2225 svf->typmod = anytime_typmod_check(false, svf->typmod);
2226 break;
2227 case SVFOP_LOCALTIMESTAMP:
2228 svf->type = TIMESTAMPOID;
2229 break;
2230 case SVFOP_LOCALTIMESTAMP_N:
2231 svf->type = TIMESTAMPOID;
2232 svf->typmod = anytimestamp_typmod_check(false, svf->typmod);
2233 break;
2234 case SVFOP_CURRENT_ROLE:
2235 case SVFOP_CURRENT_USER:
2236 case SVFOP_USER:
2237 case SVFOP_SESSION_USER:
2238 case SVFOP_CURRENT_CATALOG:
2239 case SVFOP_CURRENT_SCHEMA:
2240 svf->type = NAMEOID;
2241 break;
2242 }
2243
2244 return (Node *) svf;
2245 }
2246
2247 static Node *
transformXmlExpr(ParseState * pstate,XmlExpr * x)2248 transformXmlExpr(ParseState *pstate, XmlExpr *x)
2249 {
2250 XmlExpr *newx;
2251 ListCell *lc;
2252 int i;
2253
2254 newx = makeNode(XmlExpr);
2255 newx->op = x->op;
2256 if (x->name)
2257 newx->name = map_sql_identifier_to_xml_name(x->name, false, false);
2258 else
2259 newx->name = NULL;
2260 newx->xmloption = x->xmloption;
2261 newx->type = XMLOID; /* this just marks the node as transformed */
2262 newx->typmod = -1;
2263 newx->location = x->location;
2264
2265 /*
2266 * gram.y built the named args as a list of ResTarget. Transform each,
2267 * and break the names out as a separate list.
2268 */
2269 newx->named_args = NIL;
2270 newx->arg_names = NIL;
2271
2272 foreach(lc, x->named_args)
2273 {
2274 ResTarget *r = lfirst_node(ResTarget, lc);
2275 Node *expr;
2276 char *argname;
2277
2278 expr = transformExprRecurse(pstate, r->val);
2279
2280 if (r->name)
2281 argname = map_sql_identifier_to_xml_name(r->name, false, false);
2282 else if (IsA(r->val, ColumnRef))
2283 argname = map_sql_identifier_to_xml_name(FigureColname(r->val),
2284 true, false);
2285 else
2286 {
2287 ereport(ERROR,
2288 (errcode(ERRCODE_SYNTAX_ERROR),
2289 x->op == IS_XMLELEMENT
2290 ? errmsg("unnamed XML attribute value must be a column reference")
2291 : errmsg("unnamed XML element value must be a column reference"),
2292 parser_errposition(pstate, r->location)));
2293 argname = NULL; /* keep compiler quiet */
2294 }
2295
2296 /* reject duplicate argnames in XMLELEMENT only */
2297 if (x->op == IS_XMLELEMENT)
2298 {
2299 ListCell *lc2;
2300
2301 foreach(lc2, newx->arg_names)
2302 {
2303 if (strcmp(argname, strVal(lfirst(lc2))) == 0)
2304 ereport(ERROR,
2305 (errcode(ERRCODE_SYNTAX_ERROR),
2306 errmsg("XML attribute name \"%s\" appears more than once",
2307 argname),
2308 parser_errposition(pstate, r->location)));
2309 }
2310 }
2311
2312 newx->named_args = lappend(newx->named_args, expr);
2313 newx->arg_names = lappend(newx->arg_names, makeString(argname));
2314 }
2315
2316 /* The other arguments are of varying types depending on the function */
2317 newx->args = NIL;
2318 i = 0;
2319 foreach(lc, x->args)
2320 {
2321 Node *e = (Node *) lfirst(lc);
2322 Node *newe;
2323
2324 newe = transformExprRecurse(pstate, e);
2325 switch (x->op)
2326 {
2327 case IS_XMLCONCAT:
2328 newe = coerce_to_specific_type(pstate, newe, XMLOID,
2329 "XMLCONCAT");
2330 break;
2331 case IS_XMLELEMENT:
2332 /* no coercion necessary */
2333 break;
2334 case IS_XMLFOREST:
2335 newe = coerce_to_specific_type(pstate, newe, XMLOID,
2336 "XMLFOREST");
2337 break;
2338 case IS_XMLPARSE:
2339 if (i == 0)
2340 newe = coerce_to_specific_type(pstate, newe, TEXTOID,
2341 "XMLPARSE");
2342 else
2343 newe = coerce_to_boolean(pstate, newe, "XMLPARSE");
2344 break;
2345 case IS_XMLPI:
2346 newe = coerce_to_specific_type(pstate, newe, TEXTOID,
2347 "XMLPI");
2348 break;
2349 case IS_XMLROOT:
2350 if (i == 0)
2351 newe = coerce_to_specific_type(pstate, newe, XMLOID,
2352 "XMLROOT");
2353 else if (i == 1)
2354 newe = coerce_to_specific_type(pstate, newe, TEXTOID,
2355 "XMLROOT");
2356 else
2357 newe = coerce_to_specific_type(pstate, newe, INT4OID,
2358 "XMLROOT");
2359 break;
2360 case IS_XMLSERIALIZE:
2361 /* not handled here */
2362 Assert(false);
2363 break;
2364 case IS_DOCUMENT:
2365 newe = coerce_to_specific_type(pstate, newe, XMLOID,
2366 "IS DOCUMENT");
2367 break;
2368 }
2369 newx->args = lappend(newx->args, newe);
2370 i++;
2371 }
2372
2373 return (Node *) newx;
2374 }
2375
2376 static Node *
transformXmlSerialize(ParseState * pstate,XmlSerialize * xs)2377 transformXmlSerialize(ParseState *pstate, XmlSerialize *xs)
2378 {
2379 Node *result;
2380 XmlExpr *xexpr;
2381 Oid targetType;
2382 int32 targetTypmod;
2383
2384 xexpr = makeNode(XmlExpr);
2385 xexpr->op = IS_XMLSERIALIZE;
2386 xexpr->args = list_make1(coerce_to_specific_type(pstate,
2387 transformExprRecurse(pstate, xs->expr),
2388 XMLOID,
2389 "XMLSERIALIZE"));
2390
2391 typenameTypeIdAndMod(pstate, xs->typeName, &targetType, &targetTypmod);
2392
2393 xexpr->xmloption = xs->xmloption;
2394 xexpr->location = xs->location;
2395 /* We actually only need these to be able to parse back the expression. */
2396 xexpr->type = targetType;
2397 xexpr->typmod = targetTypmod;
2398
2399 /*
2400 * The actual target type is determined this way. SQL allows char and
2401 * varchar as target types. We allow anything that can be cast implicitly
2402 * from text. This way, user-defined text-like data types automatically
2403 * fit in.
2404 */
2405 result = coerce_to_target_type(pstate, (Node *) xexpr,
2406 TEXTOID, targetType, targetTypmod,
2407 COERCION_IMPLICIT,
2408 COERCE_IMPLICIT_CAST,
2409 -1);
2410 if (result == NULL)
2411 ereport(ERROR,
2412 (errcode(ERRCODE_CANNOT_COERCE),
2413 errmsg("cannot cast XMLSERIALIZE result to %s",
2414 format_type_be(targetType)),
2415 parser_errposition(pstate, xexpr->location)));
2416 return result;
2417 }
2418
2419 static Node *
transformBooleanTest(ParseState * pstate,BooleanTest * b)2420 transformBooleanTest(ParseState *pstate, BooleanTest *b)
2421 {
2422 const char *clausename;
2423
2424 switch (b->booltesttype)
2425 {
2426 case IS_TRUE:
2427 clausename = "IS TRUE";
2428 break;
2429 case IS_NOT_TRUE:
2430 clausename = "IS NOT TRUE";
2431 break;
2432 case IS_FALSE:
2433 clausename = "IS FALSE";
2434 break;
2435 case IS_NOT_FALSE:
2436 clausename = "IS NOT FALSE";
2437 break;
2438 case IS_UNKNOWN:
2439 clausename = "IS UNKNOWN";
2440 break;
2441 case IS_NOT_UNKNOWN:
2442 clausename = "IS NOT UNKNOWN";
2443 break;
2444 default:
2445 elog(ERROR, "unrecognized booltesttype: %d",
2446 (int) b->booltesttype);
2447 clausename = NULL; /* keep compiler quiet */
2448 }
2449
2450 b->arg = (Expr *) transformExprRecurse(pstate, (Node *) b->arg);
2451
2452 b->arg = (Expr *) coerce_to_boolean(pstate,
2453 (Node *) b->arg,
2454 clausename);
2455
2456 return (Node *) b;
2457 }
2458
2459 static Node *
transformCurrentOfExpr(ParseState * pstate,CurrentOfExpr * cexpr)2460 transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr)
2461 {
2462 /* CURRENT OF can only appear at top level of UPDATE/DELETE */
2463 Assert(pstate->p_target_nsitem != NULL);
2464 cexpr->cvarno = pstate->p_target_nsitem->p_rtindex;
2465
2466 /*
2467 * Check to see if the cursor name matches a parameter of type REFCURSOR.
2468 * If so, replace the raw name reference with a parameter reference. (This
2469 * is a hack for the convenience of plpgsql.)
2470 */
2471 if (cexpr->cursor_name != NULL) /* in case already transformed */
2472 {
2473 ColumnRef *cref = makeNode(ColumnRef);
2474 Node *node = NULL;
2475
2476 /* Build an unqualified ColumnRef with the given name */
2477 cref->fields = list_make1(makeString(cexpr->cursor_name));
2478 cref->location = -1;
2479
2480 /* See if there is a translation available from a parser hook */
2481 if (pstate->p_pre_columnref_hook != NULL)
2482 node = pstate->p_pre_columnref_hook(pstate, cref);
2483 if (node == NULL && pstate->p_post_columnref_hook != NULL)
2484 node = pstate->p_post_columnref_hook(pstate, cref, NULL);
2485
2486 /*
2487 * XXX Should we throw an error if we get a translation that isn't a
2488 * refcursor Param? For now it seems best to silently ignore false
2489 * matches.
2490 */
2491 if (node != NULL && IsA(node, Param))
2492 {
2493 Param *p = (Param *) node;
2494
2495 if (p->paramkind == PARAM_EXTERN &&
2496 p->paramtype == REFCURSOROID)
2497 {
2498 /* Matches, so convert CURRENT OF to a param reference */
2499 cexpr->cursor_name = NULL;
2500 cexpr->cursor_param = p->paramid;
2501 }
2502 }
2503 }
2504
2505 return (Node *) cexpr;
2506 }
2507
2508 /*
2509 * Construct a whole-row reference to represent the notation "relation.*".
2510 */
2511 static Node *
transformWholeRowRef(ParseState * pstate,ParseNamespaceItem * nsitem,int sublevels_up,int location)2512 transformWholeRowRef(ParseState *pstate, ParseNamespaceItem *nsitem,
2513 int sublevels_up, int location)
2514 {
2515 /*
2516 * Build the appropriate referencing node. Normally this can be a
2517 * whole-row Var, but if the nsitem is a JOIN USING alias then it contains
2518 * only a subset of the columns of the underlying join RTE, so that will
2519 * not work. Instead we immediately expand the reference into a RowExpr.
2520 * Since the JOIN USING's common columns are fully determined at this
2521 * point, there seems no harm in expanding it now rather than during
2522 * planning.
2523 *
2524 * Note that if the RTE is a function returning scalar, we create just a
2525 * plain reference to the function value, not a composite containing a
2526 * single column. This is pretty inconsistent at first sight, but it's
2527 * what we've done historically. One argument for it is that "rel" and
2528 * "rel.*" mean the same thing for composite relations, so why not for
2529 * scalar functions...
2530 */
2531 if (nsitem->p_names == nsitem->p_rte->eref)
2532 {
2533 Var *result;
2534
2535 result = makeWholeRowVar(nsitem->p_rte, nsitem->p_rtindex,
2536 sublevels_up, true);
2537
2538 /* location is not filled in by makeWholeRowVar */
2539 result->location = location;
2540
2541 /* mark relation as requiring whole-row SELECT access */
2542 markVarForSelectPriv(pstate, result);
2543
2544 return (Node *) result;
2545 }
2546 else
2547 {
2548 RowExpr *rowexpr;
2549 List *fields;
2550
2551 /*
2552 * We want only as many columns as are listed in p_names->colnames,
2553 * and we should use those names not whatever possibly-aliased names
2554 * are in the RTE. We needn't worry about marking the RTE for SELECT
2555 * access, as the common columns are surely so marked already.
2556 */
2557 expandRTE(nsitem->p_rte, nsitem->p_rtindex,
2558 sublevels_up, location, false,
2559 NULL, &fields);
2560 rowexpr = makeNode(RowExpr);
2561 rowexpr->args = list_truncate(fields,
2562 list_length(nsitem->p_names->colnames));
2563 rowexpr->row_typeid = RECORDOID;
2564 rowexpr->row_format = COERCE_IMPLICIT_CAST;
2565 rowexpr->colnames = copyObject(nsitem->p_names->colnames);
2566 rowexpr->location = location;
2567
2568 return (Node *) rowexpr;
2569 }
2570 }
2571
2572 /*
2573 * Handle an explicit CAST construct.
2574 *
2575 * Transform the argument, look up the type name, and apply any necessary
2576 * coercion function(s).
2577 */
2578 static Node *
transformTypeCast(ParseState * pstate,TypeCast * tc)2579 transformTypeCast(ParseState *pstate, TypeCast *tc)
2580 {
2581 Node *result;
2582 Node *arg = tc->arg;
2583 Node *expr;
2584 Oid inputType;
2585 Oid targetType;
2586 int32 targetTypmod;
2587 int location;
2588
2589 /* Look up the type name first */
2590 typenameTypeIdAndMod(pstate, tc->typeName, &targetType, &targetTypmod);
2591
2592 /*
2593 * If the subject of the typecast is an ARRAY[] construct and the target
2594 * type is an array type, we invoke transformArrayExpr() directly so that
2595 * we can pass down the type information. This avoids some cases where
2596 * transformArrayExpr() might not infer the correct type. Otherwise, just
2597 * transform the argument normally.
2598 */
2599 if (IsA(arg, A_ArrayExpr))
2600 {
2601 Oid targetBaseType;
2602 int32 targetBaseTypmod;
2603 Oid elementType;
2604
2605 /*
2606 * If target is a domain over array, work with the base array type
2607 * here. Below, we'll cast the array type to the domain. In the
2608 * usual case that the target is not a domain, the remaining steps
2609 * will be a no-op.
2610 */
2611 targetBaseTypmod = targetTypmod;
2612 targetBaseType = getBaseTypeAndTypmod(targetType, &targetBaseTypmod);
2613 elementType = get_element_type(targetBaseType);
2614 if (OidIsValid(elementType))
2615 {
2616 expr = transformArrayExpr(pstate,
2617 (A_ArrayExpr *) arg,
2618 targetBaseType,
2619 elementType,
2620 targetBaseTypmod);
2621 }
2622 else
2623 expr = transformExprRecurse(pstate, arg);
2624 }
2625 else
2626 expr = transformExprRecurse(pstate, arg);
2627
2628 inputType = exprType(expr);
2629 if (inputType == InvalidOid)
2630 return expr; /* do nothing if NULL input */
2631
2632 /*
2633 * Location of the coercion is preferentially the location of the :: or
2634 * CAST symbol, but if there is none then use the location of the type
2635 * name (this can happen in TypeName 'string' syntax, for instance).
2636 */
2637 location = tc->location;
2638 if (location < 0)
2639 location = tc->typeName->location;
2640
2641 result = coerce_to_target_type(pstate, expr, inputType,
2642 targetType, targetTypmod,
2643 COERCION_EXPLICIT,
2644 COERCE_EXPLICIT_CAST,
2645 location);
2646 if (result == NULL)
2647 ereport(ERROR,
2648 (errcode(ERRCODE_CANNOT_COERCE),
2649 errmsg("cannot cast type %s to %s",
2650 format_type_be(inputType),
2651 format_type_be(targetType)),
2652 parser_coercion_errposition(pstate, location, expr)));
2653
2654 return result;
2655 }
2656
2657 /*
2658 * Handle an explicit COLLATE clause.
2659 *
2660 * Transform the argument, and look up the collation name.
2661 */
2662 static Node *
transformCollateClause(ParseState * pstate,CollateClause * c)2663 transformCollateClause(ParseState *pstate, CollateClause *c)
2664 {
2665 CollateExpr *newc;
2666 Oid argtype;
2667
2668 newc = makeNode(CollateExpr);
2669 newc->arg = (Expr *) transformExprRecurse(pstate, c->arg);
2670
2671 argtype = exprType((Node *) newc->arg);
2672
2673 /*
2674 * The unknown type is not collatable, but coerce_type() takes care of it
2675 * separately, so we'll let it go here.
2676 */
2677 if (!type_is_collatable(argtype) && argtype != UNKNOWNOID)
2678 ereport(ERROR,
2679 (errcode(ERRCODE_DATATYPE_MISMATCH),
2680 errmsg("collations are not supported by type %s",
2681 format_type_be(argtype)),
2682 parser_errposition(pstate, c->location)));
2683
2684 newc->collOid = LookupCollation(pstate, c->collname, c->location);
2685 newc->location = c->location;
2686
2687 return (Node *) newc;
2688 }
2689
2690 /*
2691 * Transform a "row compare-op row" construct
2692 *
2693 * The inputs are lists of already-transformed expressions.
2694 * As with coerce_type, pstate may be NULL if no special unknown-Param
2695 * processing is wanted.
2696 *
2697 * The output may be a single OpExpr, an AND or OR combination of OpExprs,
2698 * or a RowCompareExpr. In all cases it is guaranteed to return boolean.
2699 * The AND, OR, and RowCompareExpr cases further imply things about the
2700 * behavior of the operators (ie, they behave as =, <>, or < <= > >=).
2701 */
2702 static Node *
make_row_comparison_op(ParseState * pstate,List * opname,List * largs,List * rargs,int location)2703 make_row_comparison_op(ParseState *pstate, List *opname,
2704 List *largs, List *rargs, int location)
2705 {
2706 RowCompareExpr *rcexpr;
2707 RowCompareType rctype;
2708 List *opexprs;
2709 List *opnos;
2710 List *opfamilies;
2711 ListCell *l,
2712 *r;
2713 List **opinfo_lists;
2714 Bitmapset *strats;
2715 int nopers;
2716 int i;
2717
2718 nopers = list_length(largs);
2719 if (nopers != list_length(rargs))
2720 ereport(ERROR,
2721 (errcode(ERRCODE_SYNTAX_ERROR),
2722 errmsg("unequal number of entries in row expressions"),
2723 parser_errposition(pstate, location)));
2724
2725 /*
2726 * We can't compare zero-length rows because there is no principled basis
2727 * for figuring out what the operator is.
2728 */
2729 if (nopers == 0)
2730 ereport(ERROR,
2731 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2732 errmsg("cannot compare rows of zero length"),
2733 parser_errposition(pstate, location)));
2734
2735 /*
2736 * Identify all the pairwise operators, using make_op so that behavior is
2737 * the same as in the simple scalar case.
2738 */
2739 opexprs = NIL;
2740 forboth(l, largs, r, rargs)
2741 {
2742 Node *larg = (Node *) lfirst(l);
2743 Node *rarg = (Node *) lfirst(r);
2744 OpExpr *cmp;
2745
2746 cmp = castNode(OpExpr, make_op(pstate, opname, larg, rarg,
2747 pstate->p_last_srf, location));
2748
2749 /*
2750 * We don't use coerce_to_boolean here because we insist on the
2751 * operator yielding boolean directly, not via coercion. If it
2752 * doesn't yield bool it won't be in any index opfamilies...
2753 */
2754 if (cmp->opresulttype != BOOLOID)
2755 ereport(ERROR,
2756 (errcode(ERRCODE_DATATYPE_MISMATCH),
2757 errmsg("row comparison operator must yield type boolean, "
2758 "not type %s",
2759 format_type_be(cmp->opresulttype)),
2760 parser_errposition(pstate, location)));
2761 if (expression_returns_set((Node *) cmp))
2762 ereport(ERROR,
2763 (errcode(ERRCODE_DATATYPE_MISMATCH),
2764 errmsg("row comparison operator must not return a set"),
2765 parser_errposition(pstate, location)));
2766 opexprs = lappend(opexprs, cmp);
2767 }
2768
2769 /*
2770 * If rows are length 1, just return the single operator. In this case we
2771 * don't insist on identifying btree semantics for the operator (but we
2772 * still require it to return boolean).
2773 */
2774 if (nopers == 1)
2775 return (Node *) linitial(opexprs);
2776
2777 /*
2778 * Now we must determine which row comparison semantics (= <> < <= > >=)
2779 * apply to this set of operators. We look for btree opfamilies
2780 * containing the operators, and see which interpretations (strategy
2781 * numbers) exist for each operator.
2782 */
2783 opinfo_lists = (List **) palloc(nopers * sizeof(List *));
2784 strats = NULL;
2785 i = 0;
2786 foreach(l, opexprs)
2787 {
2788 Oid opno = ((OpExpr *) lfirst(l))->opno;
2789 Bitmapset *this_strats;
2790 ListCell *j;
2791
2792 opinfo_lists[i] = get_op_btree_interpretation(opno);
2793
2794 /*
2795 * convert strategy numbers into a Bitmapset to make the intersection
2796 * calculation easy.
2797 */
2798 this_strats = NULL;
2799 foreach(j, opinfo_lists[i])
2800 {
2801 OpBtreeInterpretation *opinfo = lfirst(j);
2802
2803 this_strats = bms_add_member(this_strats, opinfo->strategy);
2804 }
2805 if (i == 0)
2806 strats = this_strats;
2807 else
2808 strats = bms_int_members(strats, this_strats);
2809 i++;
2810 }
2811
2812 /*
2813 * If there are multiple common interpretations, we may use any one of
2814 * them ... this coding arbitrarily picks the lowest btree strategy
2815 * number.
2816 */
2817 i = bms_first_member(strats);
2818 if (i < 0)
2819 {
2820 /* No common interpretation, so fail */
2821 ereport(ERROR,
2822 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2823 errmsg("could not determine interpretation of row comparison operator %s",
2824 strVal(llast(opname))),
2825 errhint("Row comparison operators must be associated with btree operator families."),
2826 parser_errposition(pstate, location)));
2827 }
2828 rctype = (RowCompareType) i;
2829
2830 /*
2831 * For = and <> cases, we just combine the pairwise operators with AND or
2832 * OR respectively.
2833 */
2834 if (rctype == ROWCOMPARE_EQ)
2835 return (Node *) makeBoolExpr(AND_EXPR, opexprs, location);
2836 if (rctype == ROWCOMPARE_NE)
2837 return (Node *) makeBoolExpr(OR_EXPR, opexprs, location);
2838
2839 /*
2840 * Otherwise we need to choose exactly which opfamily to associate with
2841 * each operator.
2842 */
2843 opfamilies = NIL;
2844 for (i = 0; i < nopers; i++)
2845 {
2846 Oid opfamily = InvalidOid;
2847 ListCell *j;
2848
2849 foreach(j, opinfo_lists[i])
2850 {
2851 OpBtreeInterpretation *opinfo = lfirst(j);
2852
2853 if (opinfo->strategy == rctype)
2854 {
2855 opfamily = opinfo->opfamily_id;
2856 break;
2857 }
2858 }
2859 if (OidIsValid(opfamily))
2860 opfamilies = lappend_oid(opfamilies, opfamily);
2861 else /* should not happen */
2862 ereport(ERROR,
2863 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2864 errmsg("could not determine interpretation of row comparison operator %s",
2865 strVal(llast(opname))),
2866 errdetail("There are multiple equally-plausible candidates."),
2867 parser_errposition(pstate, location)));
2868 }
2869
2870 /*
2871 * Now deconstruct the OpExprs and create a RowCompareExpr.
2872 *
2873 * Note: can't just reuse the passed largs/rargs lists, because of
2874 * possibility that make_op inserted coercion operations.
2875 */
2876 opnos = NIL;
2877 largs = NIL;
2878 rargs = NIL;
2879 foreach(l, opexprs)
2880 {
2881 OpExpr *cmp = (OpExpr *) lfirst(l);
2882
2883 opnos = lappend_oid(opnos, cmp->opno);
2884 largs = lappend(largs, linitial(cmp->args));
2885 rargs = lappend(rargs, lsecond(cmp->args));
2886 }
2887
2888 rcexpr = makeNode(RowCompareExpr);
2889 rcexpr->rctype = rctype;
2890 rcexpr->opnos = opnos;
2891 rcexpr->opfamilies = opfamilies;
2892 rcexpr->inputcollids = NIL; /* assign_expr_collations will fix this */
2893 rcexpr->largs = largs;
2894 rcexpr->rargs = rargs;
2895
2896 return (Node *) rcexpr;
2897 }
2898
2899 /*
2900 * Transform a "row IS DISTINCT FROM row" construct
2901 *
2902 * The input RowExprs are already transformed
2903 */
2904 static Node *
make_row_distinct_op(ParseState * pstate,List * opname,RowExpr * lrow,RowExpr * rrow,int location)2905 make_row_distinct_op(ParseState *pstate, List *opname,
2906 RowExpr *lrow, RowExpr *rrow,
2907 int location)
2908 {
2909 Node *result = NULL;
2910 List *largs = lrow->args;
2911 List *rargs = rrow->args;
2912 ListCell *l,
2913 *r;
2914
2915 if (list_length(largs) != list_length(rargs))
2916 ereport(ERROR,
2917 (errcode(ERRCODE_SYNTAX_ERROR),
2918 errmsg("unequal number of entries in row expressions"),
2919 parser_errposition(pstate, location)));
2920
2921 forboth(l, largs, r, rargs)
2922 {
2923 Node *larg = (Node *) lfirst(l);
2924 Node *rarg = (Node *) lfirst(r);
2925 Node *cmp;
2926
2927 cmp = (Node *) make_distinct_op(pstate, opname, larg, rarg, location);
2928 if (result == NULL)
2929 result = cmp;
2930 else
2931 result = (Node *) makeBoolExpr(OR_EXPR,
2932 list_make2(result, cmp),
2933 location);
2934 }
2935
2936 if (result == NULL)
2937 {
2938 /* zero-length rows? Generate constant FALSE */
2939 result = makeBoolConst(false, false);
2940 }
2941
2942 return result;
2943 }
2944
2945 /*
2946 * make the node for an IS DISTINCT FROM operator
2947 */
2948 static Expr *
make_distinct_op(ParseState * pstate,List * opname,Node * ltree,Node * rtree,int location)2949 make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree,
2950 int location)
2951 {
2952 Expr *result;
2953
2954 result = make_op(pstate, opname, ltree, rtree,
2955 pstate->p_last_srf, location);
2956 if (((OpExpr *) result)->opresulttype != BOOLOID)
2957 ereport(ERROR,
2958 (errcode(ERRCODE_DATATYPE_MISMATCH),
2959 errmsg("IS DISTINCT FROM requires = operator to yield boolean"),
2960 parser_errposition(pstate, location)));
2961 if (((OpExpr *) result)->opretset)
2962 ereport(ERROR,
2963 (errcode(ERRCODE_DATATYPE_MISMATCH),
2964 /* translator: %s is name of a SQL construct, eg NULLIF */
2965 errmsg("%s must not return a set", "IS DISTINCT FROM"),
2966 parser_errposition(pstate, location)));
2967
2968 /*
2969 * We rely on DistinctExpr and OpExpr being same struct
2970 */
2971 NodeSetTag(result, T_DistinctExpr);
2972
2973 return result;
2974 }
2975
2976 /*
2977 * Produce a NullTest node from an IS [NOT] DISTINCT FROM NULL construct
2978 *
2979 * "arg" is the untransformed other argument
2980 */
2981 static Node *
make_nulltest_from_distinct(ParseState * pstate,A_Expr * distincta,Node * arg)2982 make_nulltest_from_distinct(ParseState *pstate, A_Expr *distincta, Node *arg)
2983 {
2984 NullTest *nt = makeNode(NullTest);
2985
2986 nt->arg = (Expr *) transformExprRecurse(pstate, arg);
2987 /* the argument can be any type, so don't coerce it */
2988 if (distincta->kind == AEXPR_NOT_DISTINCT)
2989 nt->nulltesttype = IS_NULL;
2990 else
2991 nt->nulltesttype = IS_NOT_NULL;
2992 /* argisrow = false is correct whether or not arg is composite */
2993 nt->argisrow = false;
2994 nt->location = distincta->location;
2995 return (Node *) nt;
2996 }
2997
2998 /*
2999 * Produce a string identifying an expression by kind.
3000 *
3001 * Note: when practical, use a simple SQL keyword for the result. If that
3002 * doesn't work well, check call sites to see whether custom error message
3003 * strings are required.
3004 */
3005 const char *
ParseExprKindName(ParseExprKind exprKind)3006 ParseExprKindName(ParseExprKind exprKind)
3007 {
3008 switch (exprKind)
3009 {
3010 case EXPR_KIND_NONE:
3011 return "invalid expression context";
3012 case EXPR_KIND_OTHER:
3013 return "extension expression";
3014 case EXPR_KIND_JOIN_ON:
3015 return "JOIN/ON";
3016 case EXPR_KIND_JOIN_USING:
3017 return "JOIN/USING";
3018 case EXPR_KIND_FROM_SUBSELECT:
3019 return "sub-SELECT in FROM";
3020 case EXPR_KIND_FROM_FUNCTION:
3021 return "function in FROM";
3022 case EXPR_KIND_WHERE:
3023 return "WHERE";
3024 case EXPR_KIND_POLICY:
3025 return "POLICY";
3026 case EXPR_KIND_HAVING:
3027 return "HAVING";
3028 case EXPR_KIND_FILTER:
3029 return "FILTER";
3030 case EXPR_KIND_WINDOW_PARTITION:
3031 return "window PARTITION BY";
3032 case EXPR_KIND_WINDOW_ORDER:
3033 return "window ORDER BY";
3034 case EXPR_KIND_WINDOW_FRAME_RANGE:
3035 return "window RANGE";
3036 case EXPR_KIND_WINDOW_FRAME_ROWS:
3037 return "window ROWS";
3038 case EXPR_KIND_WINDOW_FRAME_GROUPS:
3039 return "window GROUPS";
3040 case EXPR_KIND_SELECT_TARGET:
3041 return "SELECT";
3042 case EXPR_KIND_INSERT_TARGET:
3043 return "INSERT";
3044 case EXPR_KIND_UPDATE_SOURCE:
3045 case EXPR_KIND_UPDATE_TARGET:
3046 return "UPDATE";
3047 case EXPR_KIND_GROUP_BY:
3048 return "GROUP BY";
3049 case EXPR_KIND_ORDER_BY:
3050 return "ORDER BY";
3051 case EXPR_KIND_DISTINCT_ON:
3052 return "DISTINCT ON";
3053 case EXPR_KIND_LIMIT:
3054 return "LIMIT";
3055 case EXPR_KIND_OFFSET:
3056 return "OFFSET";
3057 case EXPR_KIND_RETURNING:
3058 return "RETURNING";
3059 case EXPR_KIND_VALUES:
3060 case EXPR_KIND_VALUES_SINGLE:
3061 return "VALUES";
3062 case EXPR_KIND_CHECK_CONSTRAINT:
3063 case EXPR_KIND_DOMAIN_CHECK:
3064 return "CHECK";
3065 case EXPR_KIND_COLUMN_DEFAULT:
3066 case EXPR_KIND_FUNCTION_DEFAULT:
3067 return "DEFAULT";
3068 case EXPR_KIND_INDEX_EXPRESSION:
3069 return "index expression";
3070 case EXPR_KIND_INDEX_PREDICATE:
3071 return "index predicate";
3072 case EXPR_KIND_STATS_EXPRESSION:
3073 return "statistics expression";
3074 case EXPR_KIND_ALTER_COL_TRANSFORM:
3075 return "USING";
3076 case EXPR_KIND_EXECUTE_PARAMETER:
3077 return "EXECUTE";
3078 case EXPR_KIND_TRIGGER_WHEN:
3079 return "WHEN";
3080 case EXPR_KIND_PARTITION_BOUND:
3081 return "partition bound";
3082 case EXPR_KIND_PARTITION_EXPRESSION:
3083 return "PARTITION BY";
3084 case EXPR_KIND_CALL_ARGUMENT:
3085 return "CALL";
3086 case EXPR_KIND_COPY_WHERE:
3087 return "WHERE";
3088 case EXPR_KIND_GENERATED_COLUMN:
3089 return "GENERATED AS";
3090 case EXPR_KIND_CYCLE_MARK:
3091 return "CYCLE";
3092
3093 /*
3094 * There is intentionally no default: case here, so that the
3095 * compiler will warn if we add a new ParseExprKind without
3096 * extending this switch. If we do see an unrecognized value at
3097 * runtime, we'll fall through to the "unrecognized" return.
3098 */
3099 }
3100 return "unrecognized expression kind";
3101 }
3102