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Re: Is Not Null and Query Optimization

Posted by Roy Harvey on 06/28/07 16:42

On Thu, 28 Jun 2007 16:22:12 -0000, db55 <chfran@gmail.com> wrote:

>How does the phrase "Is Not Null" in the where clause effect the
>effectiveness of a query?
>
>If it is a determent to the effectiveness of the query, how do you
>work around it?
>
>Thanks,

It really isn't an issue in general, with is the only way your
question can be answered. If you provide a specific case a more
specific response might be possible.

If the requirement is to test that something is NOT NULL then it is
intrinsic to the effectiveness of the query - the query can't be
writen without it.

As far as the efficiency of the query, the optimizer will do the best
it can to take advantage of any appropriate indexes when choosing an
execution plan.

Roy Harvey
Beacon Falls, CT

 

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