Re: EXISTS / IN - does it work on Postgresql?

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От Stephan Szabo
Тема Re: EXISTS / IN - does it work on Postgresql?
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Msg-id Pine.BSF.4.21.0109191518210.69806-100000@megazone23.bigpanda.com
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Ответ на EXISTS / IN - does it work on Postgresql?  (paula@cyberlazarus.net)
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On 19 Sep 2001 paula@cyberlazarus.net wrote:

> Hello there,
>
> Finally I got a \"yes\" and I\'m moving from Microsoft SQL Server to
> Postgresql. I\'m using PHP4 and PHPLIB to work with query
> abstractions. I have a lot of subqueries like:
>
> WHERE ... EXISTS (SELECT ...)
>
> I was researching and found ambiguous information about this kind of
> subqueries, is that working fine with Postgresql?

In general, yes.  Although IN (<subquery>) queries are rather slow right
now and you might want to look at rewriting those as EXISTS (...)
instead (there's an FAQ item on this with a very simple example).


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