Re: coalesce with all nulls can only be assigned to

Kevin Grittner wrote:
>>>> On Wed, Nov 29, 2006 at 1:38 PM, in message
> <21909(dot)1164829090(at)sss(dot)pgh(dot)pa(dot)us>,
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
>>> Richard Huxton <dev(at)archonet(dot)com> wrote:
>>>> It's the coalesce that has the problem, not the insert. The
> coalesce is
>>>> deciding that it's working on text, and so returns text.
>>
>>> It seems like maybe it would be worth overloading the coalesce
> method
>>> to handle this particular case differently.
>> And do what? The only information you have is that all the inputs
> are
>> of unknown type.
>
> I know this is naive, but, what is the type information of the bare
> null? Could that be used?

A literal null is "unknown", other literals are "unknown" or
"unknown-numeric" based on quoting iirc.

Hmm - Tom would it be possible to create a cast to unknown, explicitly
cast this coalesce to unknown and let it implicitly cast back to
whatever the column needs?

--
Richard Huxton
Archonet Ltd