Re: NOT IN (NULL) ?

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От Pavel Stehule
Тема Re: NOT IN (NULL) ?
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Msg-id AANLkTi=WCJqVnH_oi5J4kph-R7R3LEedcUck5=Dm7BP+@mail.gmail.com
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Ответ на Re: NOT IN (NULL) ?  ("Paul" <magamos@mail.ru>)
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2010/10/31 Paul <magamos@mail.ru>:
> Tom,
>
> Sunday, October 31, 2010, 9:42:27 PM, you wrote:
>
> TL> Because the SQL standard says so.
>
> But  there  is  not  such  thing  in PostgreSQL as empty set as "IN ()" that must be
> false, because nothing element may be found in empty set.
> And  I  thought that instead of "IN ()" I could use "IN (NULL)", but I
> was failed and result was NULL and not FALSE. :(
>

(NULL) isn't empty set.  Empty set can be

(SELECT 1 WHERE false)

Regards

Pavel
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