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Arrange for CASE or UNION with only untyped literal constants as input

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to resolve the unknown constants as type TEXT.
This commit is contained in:
Tom Lane 2000-11-09 04:14:32 +00:00
parent 9bbca2c0f0
commit 372e598c44
1 changed files with 17 additions and 1 deletions
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18
src/backend/parser/parse_coerce.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.47 2000/10/05 19:11:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.48 2000/11/09 04:14:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -374,6 +374,22 @@ select_common_type(List *typeids, const char *context)
}
}
}
/*
* If all the inputs were UNKNOWN type --- ie, unknown-type literals ---
* then resolve as type TEXT. This situation comes up with constructs
* like
* SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END);
* SELECT 'foo' UNION SELECT 'bar';
* It might seem desirable to leave the construct's output type as
* UNKNOWN, but that really doesn't work, because we'd probably end up
* needing a runtime coercion from UNKNOWN to something else, and we
* usually won't have it. We need to coerce the unknown literals while
* they are still literals, so a decision has to be made now.
*/
if (ptype == UNKNOWNOID)
ptype = TEXTOID;
return ptype;
}