Ignore resjunk targetlist entries when matching arguments to

a SubLink with the subplan's targetlist.  This fixes a problem seen with,
for example, a subselect that uses GROUP BY.

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 48c6f9f960eab709911c5b43d4be0b2ebc63d5d0..4aecd1f04815c4677e03481954220078889c55b6 100644 (file)
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.49 1999/05/26 12:55:37 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.50 1999/07/11 02:04:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -278,7 +278,6 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                SubLink    *sublink = (SubLink *) expr;
                List       *qtrees;
                Query      *qtree;
-               List       *llist;
 
                pstate->p_hasSubLinks = true;
                qtrees = parse_analyze(lcons(sublink->subselect, NIL), pstate);
@@ -293,36 +292,48 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                if (sublink->subLinkType != EXISTS_SUBLINK)
                {
                    char       *op = lfirst(sublink->oper);
-                   List       *left_expr = sublink->lefthand;
-                   List       *right_expr = ((Query *) sublink->subselect)->targetList;
+                   List       *left_list = sublink->lefthand;
+                   List       *right_list = qtree->targetList;
                    List       *elist;
 
-                   foreach(llist, left_expr)
-                       lfirst(llist) = transformExpr(pstate, lfirst(llist), precedence);
+                   foreach(elist, left_list)
+                       lfirst(elist) = transformExpr(pstate, lfirst(elist),
+                                                     precedence);
 
-                   if (length(left_expr) != length(right_expr))
-                       elog(ERROR, "parser: Subselect has too many or too few fields.");
-
-                   if (length(left_expr) > 1 &&
+                   if (length(left_list) > 1 &&
                        strcmp(op, "=") != 0 && strcmp(op, "<>") != 0)
-                       elog(ERROR, "parser: '%s' is not relational operator", op);
+                       elog(ERROR, "parser: '%s' is not relational operator",
+                            op);
 
                    sublink->oper = NIL;
-                   foreach(elist, left_expr)
+
+                   /* Scan subquery's targetlist to find values that will be
+                    * matched against lefthand values.  We need to ignore
+                    * resjunk targets, so doing the outer iteration over
+                    * right_list is easier than doing it over left_list.
+                    */
+                   while (right_list != NIL)
                    {
-                       Node       *lexpr = lfirst(elist);
-                       Node       *rexpr = lfirst(right_expr);
-                       TargetEntry *tent = (TargetEntry *) rexpr;
+                       TargetEntry *tent = (TargetEntry *) lfirst(right_list);
+                       Node       *lexpr;
                        Expr       *op_expr;
 
-                       op_expr = make_op(op, lexpr, tent->expr);
-
-                       if (op_expr->typeOid != BOOLOID &&
-                           sublink->subLinkType != EXPR_SUBLINK)
-                           elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
-                       sublink->oper = lappend(sublink->oper, op_expr);
-                       right_expr = lnext(right_expr);
+                       if (! tent->resdom->resjunk)
+                       {
+                           if (left_list == NIL)
+                               elog(ERROR, "parser: Subselect has too many fields.");
+                           lexpr = lfirst(left_list);
+                           left_list = lnext(left_list);
+                           op_expr = make_op(op, lexpr, tent->expr);
+                           if (op_expr->typeOid != BOOLOID &&
+                               sublink->subLinkType != EXPR_SUBLINK)
+                               elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
+                           sublink->oper = lappend(sublink->oper, op_expr);
+                       }
+                       right_list = lnext(right_list);
                    }
+                   if (left_list != NIL)
+                       elog(ERROR, "parser: Subselect has too few fields.");
                }
                else
                    sublink->oper = NIL;