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Re: ORDER BY doesn't use index
Posted by: KimSeong Loh
Date: September 13, 2006 02:36AM

An index on (status,req_id) would be the best

For the subquery, the inner query is checked for every row in the outer query, that is what unique_subquery means, but only need to check 1 row in the inner query and can use the primay key to find the row to check. The inner query needs to be executed 90 times, since you have limit 0,90

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