On Thu, 24 Jul 2003, Joe Conway wrote:I see your point, but mine was that in this case I'd like a NULL returned and I don't really care about the type. ISTM that NULL should be able to morph into any type it needs to.
I don't think that's necessarily true. As a potentially absurd example, do we want select CAST( CAST( NULL as DATE ) as POINT ); to succeed when dates aren't convertable to points?
good point -- no pun intended ;)
The case of func(anyelement, anyelement) returns anyarray could potentially return some kind of "array of unknown (but single) type" when presented with unknown inputs. I'm not sure what use that'd be unless you are allowed to convert it into something else, though.
Hmm, this sounds like yet another reason for UNKNOWN[]. Specifically what I wanted to do was create a function that would give me a NULL if any arguments to my ARRAY[] expression were NULL. But the change Tom suggested (i.e. ARRAY[NULL,...] evaluates to NULL) gives me that without needing the function, so probably that is the best answer.
Joe
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