Thread: Performance of request of type WHERE ... IN ( ... )

Hello,

I have performance problem of an request of type ... WHERE ... IN ( ... ).
How to improve performance of this type of request when a group of id in the 
'in' is important.
Thanks for your answers.
Templth


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On Wed, 15 Jan 2003, Th Templ wrote:

> Hello,
>
> I have performance problem of an request of type ... WHERE ... IN ( ... ).
> How to improve performance of this type of request when a group of id in the
> 'in' is important.

Try WHERE ... EXISTS (...).


> Thanks for your answers.
> Templth
>
>
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Achilleus Mantzios
S/W Engineer
IT dept
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email:  achill@matrix.gatewaynet.com       mantzios@softlab.ece.ntua.gr

Th,

> > I have performance problem of an request of type ... WHERE ... IN (
> ... ).
> > How to improve performance of this type of request when a group of
> id in the
> > 'in' is important.
> 
> Try WHERE ... EXISTS (...).

The explanation of the difference btw. IN and EXISTS is in the
PostgreSQL FAQ on the web site.

-Josh