diff options
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 48 |
1 files changed, 45 insertions, 3 deletions
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 9705ca5d7de..3701f41dca0 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.138 2002/12/27 20:06:19 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.139 2003/01/09 20:50:52 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -367,6 +367,8 @@ transformExpr(ParseState *pstate, Node *expr) */ sublink->lefthand = NIL; sublink->oper = NIL; + sublink->operIsEquals = FALSE; + sublink->useOr = FALSE; } else if (sublink->subLinkType == EXPR_SUBLINK) { @@ -391,27 +393,60 @@ transformExpr(ParseState *pstate, Node *expr) */ sublink->lefthand = NIL; sublink->oper = NIL; + sublink->operIsEquals = FALSE; + sublink->useOr = FALSE; } else { /* ALL, ANY, or MULTIEXPR: generate operator list */ List *left_list = sublink->lefthand; List *right_list = qtree->targetList; + int row_length = length(left_list); + bool needNot = false; List *op; char *opname; List *elist; + /* transform lefthand expressions */ foreach(elist, left_list) lfirst(elist) = transformExpr(pstate, lfirst(elist)); + /* get the combining-operator name */ Assert(IsA(sublink->oper, A_Expr)); op = ((A_Expr *) sublink->oper)->name; opname = strVal(llast(op)); sublink->oper = NIL; + /* + * If the expression is "<> ALL" (with unqualified opname) + * then convert it to "NOT IN". This is a hack to improve + * efficiency of expressions output by pre-7.4 Postgres. + */ + if (sublink->subLinkType == ALL_SUBLINK && + length(op) == 1 && strcmp(opname, "<>") == 0) + { + sublink->subLinkType = ANY_SUBLINK; + opname = pstrdup("="); + op = makeList1(makeString(opname)); + needNot = true; + } + + /* Set operIsEquals if op is unqualified "=" */ + if (length(op) == 1 && strcmp(opname, "=") == 0) + sublink->operIsEquals = TRUE; + else + sublink->operIsEquals = FALSE; + + /* Set useOr if op is "<>" (possibly qualified) */ + if (strcmp(opname, "<>") == 0) + sublink->useOr = TRUE; + else + sublink->useOr = FALSE; + /* Combining operators other than =/<> is dubious... */ - if (length(left_list) != 1 && - strcmp(opname, "=") != 0 && strcmp(opname, "<>") != 0) + if (row_length != 1 && + strcmp(opname, "=") != 0 && + strcmp(opname, "<>") != 0) elog(ERROR, "Row comparison cannot use operator %s", opname); @@ -474,6 +509,13 @@ transformExpr(ParseState *pstate, Node *expr) } if (left_list != NIL) elog(ERROR, "Subselect has too few fields"); + + if (needNot) + { + expr = coerce_to_boolean(expr, "NOT"); + expr = (Node *) makeBoolExpr(NOT_EXPR, + makeList1(expr)); + } } result = (Node *) expr; break; |