|
8 | 8 | * |
9 | 9 | * |
10 | 10 | * IDENTIFICATION |
11 | | - * $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.47 2000/10/05 19:11:33 tgl Exp $ |
| 11 | + * $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.48 2000/11/09 04:14:32 tgl Exp $ |
12 | 12 | * |
13 | 13 | *------------------------------------------------------------------------- |
14 | 14 | */ |
@@ -374,6 +374,22 @@ select_common_type(List *typeids, const char *context) |
374 | 374 | } |
375 | 375 | } |
376 | 376 | } |
| 377 | + |
| 378 | +/* |
| 379 | + * If all the inputs were UNKNOWN type --- ie, unknown-type literals --- |
| 380 | + * then resolve as type TEXT. This situation comes up with constructs |
| 381 | + * like |
| 382 | + *SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END); |
| 383 | + *SELECT 'foo' UNION SELECT 'bar'; |
| 384 | + * It might seem desirable to leave the construct's output type as |
| 385 | + * UNKNOWN, but that really doesn't work, because we'd probably end up |
| 386 | + * needing a runtime coercion from UNKNOWN to something else, and we |
| 387 | + * usually won't have it. We need to coerce the unknown literals while |
| 388 | + * they are still literals, so a decision has to be made now. |
| 389 | + */ |
| 390 | +if (ptype==UNKNOWNOID) |
| 391 | +ptype=TEXTOID; |
| 392 | + |
377 | 393 | returnptype; |
378 | 394 | } |
379 | 395 |
|
|