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Fix for UNION selects with constant NULL expressions; e.g. 

SELECT 1 UNION SELECT NULL;
This commit is contained in:
Thomas G. Lockhart 1998-07-14 03:51:42 +00:00
parent 3733bd4627
commit 9fdbbdc877
1 changed files with 21 additions and 2 deletions
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23
src/backend/parser/parse_clause.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.20 1998/07/09 14:34:05 thomas Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.21 1998/07/14 03:51:42 thomas Exp $
*
*-------------------------------------------------------------------------
*/
@ -472,7 +472,25 @@ transformUnionClause(List *unionClause, List *targetlist)
Oid otype;
otype = ((TargetEntry *)lfirst(prev_target))->resdom->restype;
itype = ((TargetEntry *)lfirst(next_target))->resdom->restype;
if (itype != otype)
#ifdef PARSEDEBUG
printf("transformUnionClause: types are %d -> %d\n", itype, otype);
#endif
/* one or both is a NULL column? then don't convert... */
if (otype == InvalidOid)
{
/* propagate a known type forward, if available */
if (itype != InvalidOid)
{
((TargetEntry *)lfirst(prev_target))->resdom->restype = itype;
}
}
else if (itype == InvalidOid)
{
}
/* they don't match in type? then convert... */
else if (itype != otype)
{
Node *expr;
@ -488,6 +506,7 @@ transformUnionClause(List *unionClause, List *targetlist)
((TargetEntry *)lfirst(next_target))->expr = expr;
((TargetEntry *)lfirst(next_target))->resdom->restype = otype;
}
/* both are UNKNOWN? then evaluate as text... */
else if (itype == UNKNOWNOID)
{