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Implement subselects in target lists. Also, relax requirement that

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subselects can only appear on the righthand side of a binary operator.
That's still true for quantified predicates like x = ANY (SELECT ...),
but a subselect that delivers a single result can now appear anywhere
in an expression.  This is implemented by changing EXPR_SUBLINK sublinks
to represent just the (SELECT ...) expression, without any 'left hand
side' or combining operator --- so they're now more like EXISTS_SUBLINK.
To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink
type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to.
But the grammar will only generate one for a multiple-left-hand-side
row expression.
This commit is contained in:
Tom Lane
1999-11-15 02:00:15 +00:00
parent 1ecb129d20
commit f68e11f373
12 changed files with 364 additions and 566 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
src/backend/parser/analyze.c
View File

@@ -5,7 +5,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: analyze.c,v 1.123 1999/11/07 23:08:10 momjian Exp $
* $Id: analyze.c,v 1.124 1999/11/15 02:00:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -231,11 +231,11 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
/* fix where clause */
qry->qual = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->rtable = pstate->p_rtable;
qry->resultRelation = refnameRangeTablePosn(pstate, stmt->relname, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs)
parseCheckAggregates(pstate, qry);
@@ -423,6 +423,9 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
if (stmt->forUpdate != NULL)
transformForUpdate(qry, stmt->forUpdate);
/* in case of subselects in default clauses... */
qry->hasSubLinks = pstate->p_hasSubLinks;
return (Query *) qry;
}

405
src/backend/parser/gram.y
View File

@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.113 1999/10/29 23:52:20 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.114 1999/11/15 02:00:10 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -53,11 +53,12 @@
#include "mb/pg_wchar.h"
#endif
extern List *parsetree; /* final parse result is delivered here */
static char saved_relname[NAMEDATALEN]; /* need this for complex attributes */
static bool QueryIsRule = FALSE;
static Oid *param_type_info;
static int pfunc_num_args;
extern List *parsetree;
/*
@@ -75,8 +76,6 @@ static void mapTargetColumns(List *source, List *target);
static void param_type_init(Oid *typev, int nargs);
static Node *doNegate(Node *n);
Oid param_type(int t); /* used in parse_expr.c */
/* old versions of flex define this as a macro */
#if defined(yywrap)
#undef yywrap
@@ -178,7 +177,7 @@ Oid param_type(int t); /* used in parse_expr.c */
%type <boolean> TriggerForOpt, TriggerForType, OptTemp, OptTempType, OptTempScope
%type <list> for_update_clause, update_list
%type <boolean> opt_union
%type <boolean> opt_all
%type <boolean> opt_table
%type <boolean> opt_trans
@@ -1097,11 +1096,18 @@ OptInherit: INHERITS '(' relation_name_list ')' { $$ = $3; }
| /*EMPTY*/ { $$ = NIL; }
;
CreateAsStmt: CREATE OptTemp TABLE relation_name OptCreateAs AS SubSelect
/*
* Note: CREATE TABLE ... AS SELECT ... is just another spelling for
* SELECT ... INTO.
*/
CreateAsStmt: CREATE OptTemp TABLE relation_name OptCreateAs AS SelectStmt
{
SelectStmt *n = (SelectStmt *)$7;
if ($5 != NIL)
mapTargetColumns($5, n->targetList);
if (n->into != NULL)
elog(ERROR,"CREATE TABLE/AS SELECT may not specify INTO");
n->istemp = $2;
n->into = $4;
$$ = (Node *)n;
@@ -2861,7 +2867,7 @@ select_clause: '(' select_clause ')'
$$ = (Node *)makeA_Expr(AND,NULL,$1,
makeA_Expr(NOT,NULL,NULL,$3));
}
| select_clause UNION opt_union select_clause
| select_clause UNION opt_all select_clause
{
if (IsA($4, SelectStmt))
{
@@ -2919,7 +2925,7 @@ opt_table: TABLE { $$ = TRUE; }
| /*EMPTY*/ { $$ = FALSE; }
;
opt_union: ALL { $$ = TRUE; }
opt_all: ALL { $$ = TRUE; }
| /*EMPTY*/ { $$ = FALSE; }
;
@@ -3590,16 +3596,13 @@ a_expr_or_null: a_expr
* Define row_descriptor to allow yacc to break the reduce/reduce conflict
* with singleton expressions.
* Eliminated lots of code by defining row_op and sub_type clauses.
* However, can not consolidate EXPR_LINK case with others subselects
* due to shift/reduce conflict with the non-subselect clause (the parser
* would have to look ahead more than one token to resolve the conflict).
* - thomas 1998-05-09
*/
row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = $2;
n->oper = lcons("=",NIL);
n->oper = lcons("=", NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $6;
@@ -3609,7 +3612,7 @@ row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = $2;
n->oper = lcons("<>",NIL);
n->oper = lcons("<>", NIL);
n->useor = true;
n->subLinkType = ALL_SUBLINK;
n->subselect = $7;
@@ -3637,7 +3640,7 @@ row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
n->useor = true;
else
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subLinkType = MULTIEXPR_SUBLINK;
n->subselect = $6;
$$ = (Node *)n;
}
@@ -3933,16 +3936,6 @@ a_expr: attr
n->args = NIL;
$$ = (Node *)n;
}
| EXISTS '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = NIL;
n->useor = false;
n->oper = NIL;
n->subLinkType = EXISTS_SUBLINK;
n->subselect = $3;
$$ = (Node *)n;
}
| EXTRACT '(' extract_list ')'
{
FuncCall *n = makeNode(FuncCall);
@@ -4065,7 +4058,7 @@ a_expr: attr
{
SubLink *n = (SubLink *)$4;
n->lefthand = lcons($1, NIL);
n->oper = lcons("=",NIL);
n->oper = lcons("=", NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
$$ = (Node *)n;
@@ -4092,7 +4085,7 @@ a_expr: attr
{
SubLink *n = (SubLink *)$5;
n->lefthand = lcons($1, NIL);
n->oper = lcons("<>",NIL);
n->oper = lcons("<>", NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
$$ = (Node *)n;
@@ -4112,334 +4105,34 @@ a_expr: attr
$$ = n;
}
}
| a_expr Op '(' SubSelect ')'
| a_expr row_op sub_type '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons($2,NIL);
n->lefthand = lcons($1, NIL);
n->oper = lcons($2, NIL);
n->useor = false; /* doesn't matter since only one col */
n->subLinkType = $3;
n->subselect = $5;
$$ = (Node *)n;
}
| EXISTS '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = NIL;
n->oper = NIL;
n->useor = false;
n->subLinkType = EXISTS_SUBLINK;
n->subselect = $3;
$$ = (Node *)n;
}
| '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = NIL;
n->oper = NIL;
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '+' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("+",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '-' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("-",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '*' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("*",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '/' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("/",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '%' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("%",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '^' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("^",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '|' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("|",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '<' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("<",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '>' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons(">",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr '=' '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("=",NIL);
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $4;
$$ = (Node *)n;
}
| a_expr Op ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons($2,NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '+' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("+",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '-' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("-",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '*' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("*",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '/' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("/",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '%' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("%",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '^' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("^",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '|' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("|",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '<' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("<",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '>' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons(">",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '=' ANY '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1,NIL);
n->oper = lcons("=",NIL);
n->useor = false;
n->subLinkType = ANY_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr Op ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons($2,NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '+' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("+",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '-' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("-",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '*' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("*",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '/' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("/",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '%' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("%",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '^' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("^",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '|' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("|",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '<' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("<",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '>' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons(">",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
$$ = (Node *)n;
}
| a_expr '=' ALL '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NULL);
n->oper = lcons("=",NIL);
n->useor = false;
n->subLinkType = ALL_SUBLINK;
n->subselect = $5;
n->subselect = $2;
$$ = (Node *)n;
}
| a_expr AND a_expr
@@ -4702,6 +4395,16 @@ b_expr: attr
n->args = $3;
$$ = (Node *)n;
}
| '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = NIL;
n->oper = NIL;
n->useor = false;
n->subLinkType = EXPR_SUBLINK;
n->subselect = $2;
$$ = (Node *)n;
}
;
opt_indirection: '[' a_expr ']' opt_indirection
@@ -5345,8 +5048,6 @@ mapTargetColumns(List *src, List *dst)
src = lnext(src);
dst = lnext(dst);
}
return;
} /* mapTargetColumns() */

45
src/backend/parser/parse_expr.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.58 1999/09/13 04:14:56 thomas Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.59 1999/11/15 02:00:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -220,8 +220,30 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
sublink->lefthand = NIL;
sublink->oper = NIL;
}
else if (sublink->subLinkType == EXPR_SUBLINK)
{
List *tlist = qtree->targetList;
/* Make sure the subselect delivers a single column
* (ignoring resjunk targets).
*/
if (tlist == NIL ||
((TargetEntry *) lfirst(tlist))->resdom->resjunk)
elog(ERROR, "parser: subselect must have a field");
while ((tlist = lnext(tlist)) != NIL)
{
if (! ((TargetEntry *) lfirst(tlist))->resdom->resjunk)
elog(ERROR, "parser: subselect must have only one field");
}
/* EXPR needs no lefthand or combining operator.
* These fields should be NIL already, but make sure.
*/
sublink->lefthand = NIL;
sublink->oper = NIL;
}
else
{
/* ALL, ANY, or MULTIEXPR: generate operator list */
char *op = lfirst(sublink->oper);
List *left_list = sublink->lefthand;
List *right_list = qtree->targetList;
@@ -231,9 +253,10 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
lfirst(elist) = transformExpr(pstate, lfirst(elist),
precedence);
if (length(left_list) > 1 &&
/* Combining operators other than =/<> is dubious... */
if (length(left_list) != 1 &&
strcmp(op, "=") != 0 && strcmp(op, "<>") != 0)
elog(ERROR, "parser: '%s' is not relational operator",
elog(ERROR, "parser: '%s' is not usable for row comparison",
op);
sublink->oper = NIL;
@@ -266,8 +289,7 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
FALSE);
opform = (Form_pg_operator) GETSTRUCT(optup);
if (opform->oprresult != BOOLOID &&
sublink->subLinkType != EXPR_SUBLINK)
if (opform->oprresult != BOOLOID)
elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
newop = makeOper(oprid(optup),/* opno */
@@ -589,13 +611,14 @@ exprType(Node *expr)
if (sublink->subLinkType == EXPR_SUBLINK)
{
/* return the result type of the combining operator;
* should only be one...
*/
Oper *op = (Oper *) lfirst(sublink->oper);
/* get the type of the subselect's first target column */
Query *qtree = (Query *) sublink->subselect;
TargetEntry *tent;
Assert(IsA(op, Oper));
type = op->opresulttype;
if (! qtree || ! IsA(qtree, Query))
elog(ERROR, "exprType: can't get type for untransformed sublink");
tent = (TargetEntry *) lfirst(qtree->targetList);
type = tent->resdom->restype;
}
else
{