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Re: Performance impact of filtering in ON vs WHERE clause
Posted by: Apachez
Date: May 02, 2006 01:15PM

The USING was just an example which shows you how joins are being handled by the server. Any filtering should be done in the WHERE part, the join statement only tells the server which columns relate to each other.

However the optimizer will most likely try to fix you badly written "filter inside join statement" so it will be a proper "join statement" along with a "filtering in the WHERE part".

An EXPLAIN SELECT should show you what happends...

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Re: Performance impact of filtering in ON vs WHERE clause
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