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Re: running running running
Posted by: Øystein Grøvlen
Date: January 31, 2012 07:54AM

Hard to say whether it is correct, since I do not know what you want to achieve, but I do not think the queries are equivalent since you are replacing LEFT JOIN with INNER JOIN.

By the way, what is the '{OJ ...}' syntax? It is not something that MySQL will understand., AFAIK.

Long query optimization times may be caused by the optimizer evaluating very many query plans when a large number of tables are joined. This should be less of a problem when OUTER JOINS are used, but just to rule out this, you can try setting optimizer_search_depth variable to a low number (e.g., 4) to see if that helps.

Øystein Grøvlen,
Senior Principal Software Engineer,
MySQL Group, Oracle,
Trondheim, Norway

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