On Tue, Sep 2, 2008 at 10:58 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Richard Broersma" <richard.broersma@gmail.com> writes:
>> There is one possible alteration that may or many not improve
>> performance. This would be to replace the EXISTS with a LEFT JOIN
>> WHERE IS NOT NULL;
>
> That changes the behavior, doesn't it? Or is event_log_no a unique
> key for Myevents? I think what you want is to make the EXISTS an IN
> instead.
Thanks for pointing that out Tom. I hadn't consider how the EXISTS
clause would return potentially fewer rows if event_log_no wasn't
unique.
--
Regards,
Richard Broersma Jr.
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