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https://github.com/postgres/postgres.git
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Adjust parser so that 'x NOT IN (subselect)' is converted to
'NOT (x IN (subselect))', that is 'NOT (x = ANY (subselect))', rather than 'x <> ALL (subselect)' as we formerly did. This opens the door to optimizing NOT IN the same way as IN, whereas there's no hope of optimizing the expression using <>. Also, convert 'x <> ALL (subselect)' to the NOT(IN) style, so that the optimization will be available when processing rules dumped by older Postgres versions. initdb forced due to small change in SubLink node representation.
This commit is contained in:
Tom Lane
@ -11,7 +11,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.391 2003/01/08 00:22:27 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.392 2003/01/09 20:50:51 tgl Exp $
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*
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* HISTORY
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* AUTHOR DATE MAJOR EVENT
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@ -5420,28 +5420,30 @@ opt_interval:
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/* Expressions using row descriptors
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* Define row_descriptor to allow yacc to break the reduce/reduce conflict
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* with singleton expressions. Use SQL99's ROW keyword to allow rows of
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* one element.
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* with singleton expressions. Use SQL99's ROW keyword to allow rows of
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* one element.
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*/
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r_expr: row IN_P select_with_parens
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{
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SubLink *n = makeNode(SubLink);
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n->lefthand = $1;
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n->oper = (List *) makeSimpleA_Expr(OP, "=", NULL, NULL);
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n->useor = FALSE;
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n->subLinkType = ANY_SUBLINK;
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/* operIsEquals and useOr will be set later */
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n->subselect = $3;
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$$ = (Node *)n;
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}
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| row NOT IN_P select_with_parens
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{
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/* Make an IN node */
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SubLink *n = makeNode(SubLink);
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n->lefthand = $1;
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n->oper = (List *) makeSimpleA_Expr(OP, "<>", NULL, NULL);
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n->useor = TRUE;
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n->subLinkType = ALL_SUBLINK;
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n->oper = (List *) makeSimpleA_Expr(OP, "=", NULL, NULL);
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n->subLinkType = ANY_SUBLINK;
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/* operIsEquals and useOr will be set later */
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n->subselect = $4;
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$$ = (Node *)n;
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/* Stick a NOT on top */
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$$ = (Node *) makeA_Expr(NOT, NIL, NULL, (Node *) n);
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}
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| row qual_all_Op sub_type select_with_parens
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%prec Op
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@ -5449,11 +5451,8 @@ r_expr: row IN_P select_with_parens
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SubLink *n = makeNode(SubLink);
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n->lefthand = $1;
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n->oper = (List *) makeA_Expr(OP, $2, NULL, NULL);
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if (strcmp(strVal(llast($2)), "<>") == 0)
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n->useor = TRUE;
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else
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n->useor = FALSE;
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n->subLinkType = $3;
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/* operIsEquals and useOr will be set later */
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n->subselect = $4;
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$$ = (Node *)n;
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}
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@ -5463,11 +5462,8 @@ r_expr: row IN_P select_with_parens
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SubLink *n = makeNode(SubLink);
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n->lefthand = $1;
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n->oper = (List *) makeA_Expr(OP, $2, NULL, NULL);
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if (strcmp(strVal(llast($2)), "<>") == 0)
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n->useor = TRUE;
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else
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n->useor = FALSE;
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n->subLinkType = MULTIEXPR_SUBLINK;
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/* operIsEquals and useOr will be set later */
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n->subselect = $3;
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$$ = (Node *)n;
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}
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@ -5850,8 +5846,8 @@ a_expr: c_expr { $$ = $1; }
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SubLink *n = (SubLink *)$3;
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n->lefthand = makeList1($1);
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n->oper = (List *) makeSimpleA_Expr(OP, "=", NULL, NULL);
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n->useor = FALSE;
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n->subLinkType = ANY_SUBLINK;
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/* operIsEquals and useOr will be set later */
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$$ = (Node *)n;
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}
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else
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@ -5875,12 +5871,14 @@ a_expr: c_expr { $$ = $1; }
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/* in_expr returns a SubLink or a list of a_exprs */
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if (IsA($4, SubLink))
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{
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/* Make an IN node */
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SubLink *n = (SubLink *)$4;
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n->lefthand = makeList1($1);
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n->oper = (List *) makeSimpleA_Expr(OP, "<>", NULL, NULL);
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n->useor = FALSE;
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n->subLinkType = ALL_SUBLINK;
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$$ = (Node *)n;
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n->oper = (List *) makeSimpleA_Expr(OP, "=", NULL, NULL);
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n->subLinkType = ANY_SUBLINK;
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/* operIsEquals and useOr will be set later */
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/* Stick a NOT on top */
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$$ = (Node *) makeA_Expr(NOT, NIL, NULL, (Node *) n);
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}
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else
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{
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@ -5903,8 +5901,8 @@ a_expr: c_expr { $$ = $1; }
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SubLink *n = makeNode(SubLink);
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n->lefthand = makeList1($1);
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n->oper = (List *) makeA_Expr(OP, $2, NULL, NULL);
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n->useor = FALSE; /* doesn't matter since only one col */
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n->subLinkType = $3;
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/* operIsEquals and useOr will be set later */
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n->subselect = $4;
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$$ = (Node *)n;
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}
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@ -6447,7 +6445,6 @@ c_expr: columnref { $$ = (Node *) $1; }
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SubLink *n = makeNode(SubLink);
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n->lefthand = NIL;
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n->oper = NIL;
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n->useor = FALSE;
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n->subLinkType = EXPR_SUBLINK;
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n->subselect = $1;
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$$ = (Node *)n;
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@ -6457,7 +6454,6 @@ c_expr: columnref { $$ = (Node *) $1; }
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SubLink *n = makeNode(SubLink);
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n->lefthand = NIL;
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n->oper = NIL;
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n->useor = FALSE;
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n->subLinkType = EXISTS_SUBLINK;
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n->subselect = $2;
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$$ = (Node *)n;
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.138 2002/12/27 20:06:19 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.139 2003/01/09 20:50:52 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -367,6 +367,8 @@ transformExpr(ParseState *pstate, Node *expr)
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*/
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sublink->lefthand = NIL;
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sublink->oper = NIL;
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sublink->operIsEquals = FALSE;
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sublink->useOr = FALSE;
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}
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else if (sublink->subLinkType == EXPR_SUBLINK)
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{
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@ -391,27 +393,60 @@ transformExpr(ParseState *pstate, Node *expr)
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*/
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sublink->lefthand = NIL;
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sublink->oper = NIL;
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sublink->operIsEquals = FALSE;
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sublink->useOr = FALSE;
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}
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else
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{
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/* ALL, ANY, or MULTIEXPR: generate operator list */
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List *left_list = sublink->lefthand;
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List *right_list = qtree->targetList;
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int row_length = length(left_list);
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bool needNot = false;
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List *op;
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char *opname;
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List *elist;
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/* transform lefthand expressions */
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foreach(elist, left_list)
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lfirst(elist) = transformExpr(pstate, lfirst(elist));
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/* get the combining-operator name */
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Assert(IsA(sublink->oper, A_Expr));
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op = ((A_Expr *) sublink->oper)->name;
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opname = strVal(llast(op));
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sublink->oper = NIL;
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/*
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* If the expression is "<> ALL" (with unqualified opname)
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* then convert it to "NOT IN". This is a hack to improve
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* efficiency of expressions output by pre-7.4 Postgres.
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*/
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if (sublink->subLinkType == ALL_SUBLINK &&
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length(op) == 1 && strcmp(opname, "<>") == 0)
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{
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sublink->subLinkType = ANY_SUBLINK;
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opname = pstrdup("=");
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op = makeList1(makeString(opname));
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needNot = true;
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}
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/* Set operIsEquals if op is unqualified "=" */
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if (length(op) == 1 && strcmp(opname, "=") == 0)
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sublink->operIsEquals = TRUE;
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else
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sublink->operIsEquals = FALSE;
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/* Set useOr if op is "<>" (possibly qualified) */
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if (strcmp(opname, "<>") == 0)
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sublink->useOr = TRUE;
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else
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sublink->useOr = FALSE;
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/* Combining operators other than =/<> is dubious... */
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if (length(left_list) != 1 &&
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strcmp(opname, "=") != 0 && strcmp(opname, "<>") != 0)
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if (row_length != 1 &&
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strcmp(opname, "=") != 0 &&
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strcmp(opname, "<>") != 0)
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elog(ERROR, "Row comparison cannot use operator %s",
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opname);
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@ -474,6 +509,13 @@ transformExpr(ParseState *pstate, Node *expr)
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}
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if (left_list != NIL)
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elog(ERROR, "Subselect has too few fields");
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if (needNot)
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{
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expr = coerce_to_boolean(expr, "NOT");
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expr = (Node *) makeBoolExpr(NOT_EXPR,
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makeList1(expr));
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}
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}
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result = (Node *) expr;
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break;
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