Re: NOT IN, SQL, Optimisation

From: Volker Neurath <neanderix_at_gmx.de>
Date: Wed, 14 Nov 2001 21:26:35 +0100
Message-ID: <9sujpk$15gfj2$1@ID-29596.news.dfncis.de>

Francois Baviere wrote:

>Hi,
>
>I worked quite a bit to find out a SQL sentence to look for some specific
>records in my database. I was quite surprise by the way NOT IN is working.
>However I have found something which work.... however it is very long....

If you wonder, why your query is still working:

you know that NOT IN is doing a full table scan for each value delivered by the subqueries?

Therefore i try not to use NOT IN but to use NOT EXISTS in stead of it.

Volker Received on Wed Nov 14 2001 - 14:26:35 CST