diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/executor/nodeSubplan.c | 55 | ||||
| -rw-r--r-- | src/backend/parser/parse_expr.c | 25 |
2 files changed, 57 insertions, 23 deletions
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index 9f872c60682..2eebbf1f1e2 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -29,10 +29,11 @@ ExecSubPlan(SubPlan *node, List *pvar, ExprContext *econtext) { Plan *plan = node->plan; SubLink *sublink = node->sublink; + SubLinkType subLinkType = sublink->subLinkType; TupleTableSlot *slot; List *lst; - bool result = false; - bool found = false; + Datum result = (Datum) false; + bool found = false; /* TRUE if got at least one subplan tuple */ if (node->setParam != NULL) elog(ERROR, "ExecSubPlan: can't set parent params from subquery"); @@ -56,6 +57,18 @@ ExecSubPlan(SubPlan *node, List *pvar, ExprContext *econtext) ExecReScan(plan, (ExprContext *) NULL, plan); + /* + * For all sublink types except EXPR_SUBLINK, the result type is boolean, + * and we have a fairly clear idea of how to combine multiple subitems + * and deal with NULL values or an empty subplan result. + * + * For EXPR_SUBLINK, the result type is whatever the combining operator + * returns. We have no way to deal with more than one column in the + * subplan result --- hopefully the parser forbids that. More seriously, + * it's unclear what to do with NULL values or an empty subplan result. + * For now, we error out, but should something else happen? + */ + for (slot = ExecProcNode(plan, plan); !TupIsNull(slot); slot = ExecProcNode(plan, plan)) @@ -64,13 +77,13 @@ ExecSubPlan(SubPlan *node, List *pvar, ExprContext *econtext) TupleDesc tdesc = slot->ttc_tupleDescriptor; int i = 1; - if (sublink->subLinkType == EXPR_SUBLINK && found) + if (subLinkType == EXPR_SUBLINK && found) { elog(ERROR, "ExecSubPlan: more than one tuple returned by expression subselect"); return (Datum) false; } - if (sublink->subLinkType == EXISTS_SUBLINK) + if (subLinkType == EXISTS_SUBLINK) return (Datum) true; found = true; @@ -82,23 +95,39 @@ ExecSubPlan(SubPlan *node, List *pvar, ExprContext *econtext) bool isnull; con->constvalue = heap_getattr(tup, i, tdesc, &(con->constisnull)); - result = (bool) ExecEvalExpr((Node *) expr, econtext, &isnull, (bool *) NULL); + result = ExecEvalExpr((Node *) expr, econtext, &isnull, (bool *) NULL); if (isnull) - result = false; - if ((!result && !(sublink->useor)) || (result && sublink->useor)) - break; + { + if (subLinkType == EXPR_SUBLINK) + elog(ERROR, "ExecSubPlan: null value returned by expression subselect"); + else + result = (Datum) false; + } + if (subLinkType != EXPR_SUBLINK) + { + if ((! (bool) result && !(sublink->useor)) || + ((bool) result && sublink->useor)) + break; + } i++; } - if ((!result && sublink->subLinkType == ALL_SUBLINK) || - (result && sublink->subLinkType == ANY_SUBLINK)) + if (subLinkType == ALL_SUBLINK && ! (bool) result) + break; + if (subLinkType == ANY_SUBLINK && (bool) result) break; } - if (!found && sublink->subLinkType == ALL_SUBLINK) - return (Datum) true; + if (!found) + { + /* deal with empty subplan result. Note default result is 'false' */ + if (subLinkType == ALL_SUBLINK) + result = (Datum) true; + else if (subLinkType == EXPR_SUBLINK) + elog(ERROR, "ExecSubPlan: no tuples returned by expression subselect"); + } - return (Datum) result; + return result; } /* ---------------------------------------------------------------- diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index d23d7214a34..f18fbd46eed 100644 --- 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 1.41 1999/04/18 17:35:51 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.42 1999/04/19 04:17:11 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -312,14 +312,6 @@ transformExpr(ParseState *pstate, Node *expr, int precedence) op_expr = make_op(op, lexpr, tent->expr); - /* - * HACK! Second IF is more valid but currently we - * don't support EXPR subqueries inside - * expressions generally, only in WHERE clauses. - * After fixing this, first IF must be removed. - */ - if (op_expr->typeOid != BOOLOID) - elog(ERROR, "parser: '%s' must return 'bool' to be used with subquery", op); if (op_expr->typeOid != BOOLOID && sublink->subLinkType != EXPR_SUBLINK) elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op); @@ -598,7 +590,20 @@ exprType(Node *expr) type = ((Param *) expr)->paramtype; break; case T_SubLink: - type = BOOLOID; + { + SubLink *sublink = (SubLink *) expr; + if (sublink->subLinkType == EXPR_SUBLINK) + { + /* return the result type of the combining operator */ + Expr *op_expr = (Expr *) lfirst(sublink->oper); + type = op_expr->typeOid; + } + else + { + /* for all other sublink types, result is boolean */ + type = BOOLOID; + } + } break; case T_CaseExpr: type = ((CaseExpr *) expr)->casetype; |