Re: COALESCE and NULLIF semantics

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От Jeff Davis
Тема Re: COALESCE and NULLIF semantics
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Msg-id 1252703960.9975.89.camel@monkey-cat.sm.truviso.com
обсуждение исходный текст
Ответ на Re: COALESCE and NULLIF semantics  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: COALESCE and NULLIF semantics  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-hackers
On Fri, 2009-09-11 at 12:59 -0400, Tom Lane wrote:
> If so then ROW(NULL,NULL) would be
> indistinguishable from NULL and the semantic gripes seem to largely
> go away.  It would be a problem for anyone who actually wanted to
> distinguish those two cases, but how much do we care?

Does that violate the standard?

To make that interpretation work I think you would need to say that
ROW(NULL,NULL) _is_ the null value, and you would have to allow things
like:
 select 1 + row(null,null);

which seems strange to me.

Regards,Jeff Davis




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