On Wed, 15 Jan 2003, Tom Lane wrote: > Stephan Szabo <[EMAIL PROTECTED]> writes: > > It seems to me that the spec has a fairly hardwired notion of what types > > should come out given the sql types. The biggest problems that I can > > see are that it doesn't extend well to an extensible type system and that > > in alot of cases it doesn't seem to allow conversions (for example > > select CAST(1 as float) union select '1' - if you were to allow > > conversions the rules seem to be ambiguous) > > Agreed, we can't make use of the spec's rules as anything much better > than "spiritual guidance". But it'd be nice if the rules we use match > what the spec says for the cases covered by the spec. In particular, > I think it's intuitively correct that numeric union int should yield > numeric no matter which order you write them in. > > Actually, now that I look at the code, 7.3 does in fact get this case > right, because we did add a check on pg_cast: it will prefer a type over > another if there is an implicit cast in only one direction.
> The OP may have been fooled by this behavior: > > regression=# select 1 union select 1.0; And I was fooled by select '1' union select 1; because I'd forgotten that '1' isn't exactly a character string constant. select '1'::text union select 1; properly errors. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
