Re: [BUGS] (null) != (null) ?

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От Todd Vierling
Тема Re: [BUGS] (null) != (null) ?
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Msg-id Pine.NEB.4.10.9910261145270.26623-100000@server.int.duh.org
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Ответ на Re: [BUGS] (null) != (null) ?  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Tue, 26 Oct 1999, Tom Lane wrote:

: > => select * from foo2 where field not in (select field from foo);

: Well, it falls out of the semantics:  the NOT IN is true if foo2's
: field is not equal to *all* of the entries returned by the subselect.
: If one of those is NULL, then the result of the NOT IN can't be "true",
: it has to be "unknown",

In this case, I suppose I can produce another workaround:

select * from foo where field not in
  (select field from foo2 where field notnull);

which is more wordy, but seems to work as I want.

Thanks for the help!

--
-- Todd Vierling (tv@pobox.com)


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