Re: [PERFORM] Hypothetical suggestions for planner, indexing improvement

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От Tom Lane
Тема Re: [PERFORM] Hypothetical suggestions for planner, indexing improvement
Дата
Msg-id 24779.1052228707@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Hypothetical suggestions for planner, indexing improvement  (Josh Berkus <josh@agliodbs.com>)
Ответы Re: [PERFORM] Hypothetical suggestions for planner, indexing
Re: [PERFORM] Hypothetical suggestions for planner, indexing improvement
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"Jim C. Nasby" <jim@nasby.net> writes:
> It would be nice to add support for multi-column IN..
> WHERE (a, b, c) IN (SELECT a, b, c ...)

RTFM...

> BTW, does postgresql handle IN and EXISTS differently?

Yes.

> Theoretically if the optimizer was good enough you could transform one
> to the other and not worry about it.

No.  They have different responses to NULLs in the subselect result.

            regards, tom lane

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