Re: join query question

On Fri, 22 Jun 2001 22:49:55 -0500, john sprague <bearpig_at_attglobal.net> wrote:

>
> I'm going to have to go look at my performance text now - you've got me wondering.
>What you say seems reasonable for tables of approximately equal size - but I have a '
>avoid negation' clause in my head - and not just from blowing indexes. I'll have to
>dig.
>
>You're right, maybe I am smelling 'vanilla' because somebody said it - not because it is
>in the air. I'll look .
>
>jds

I had a scenario very recently where I was asked to help in a query. After banging my head against the wall I realized that he was using negation where he should not have. Only looking for what he needed made a seemingly complex query quite easy. So, I do believe in avoiding negation, unless that is exactly what the requirements are.

As far as when (NOT) EXISTS is better than a join, I do not know. That's one reason I subscribe to this newsgroup!

Brian Received on Sun Jun 24 2001 - 10:31:35 CDT