The resolution to my problem with the select_common_type() error message
turned out to be that this doesn't work:
postgres=# select null union select null union select 1;
ERROR: UNION types text and integer cannot be matched
That's because it resolves the first two branches independently, then
Peter Eisentraut [EMAIL PROTECTED] writes:
The resolution to my problem with the select_common_type() error message
turned out to be that this doesn't work:
postgres=# select null union select null union select 1;
ERROR: UNION types text and integer cannot be matched
Yeah, this has been
Tom Lane [EMAIL PROTECTED] writes:
Maybe we should just ignore those qualms and do it anyway --- I must
admit that I'm hard-pressed to come up with a situation where anyone
would really want different datatypes used in the inner union than
the outer.
Does it even matter except in the case of
Gregory Stark [EMAIL PROTECTED] writes:
Tom Lane [EMAIL PROTECTED] writes:
Maybe we should just ignore those qualms and do it anyway --- I must
admit that I'm hard-pressed to come up with a situation where anyone
would really want different datatypes used in the inner union than
the outer.
Tom Lane [EMAIL PROTECTED] writes:
Gregory Stark [EMAIL PROTECTED] writes:
Does it even matter except in the case of nulls? I mean, if the inner pair
uses integer and then the outer pair uses bigint it'll still work correctly,
no?
Oh, it absolutely matters: you can get different answers.
Am Dienstag, 24. April 2007 19:48 schrieb Tom Lane:
You're missing the point, which is that the inner UNION needs to decide
what its uniqueness semantics are, independently of what might happen to
its result later. Or that's how I read the spec anyway.
It's probably safer to leave it as is.
