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Re: Performance of WHERE EXISTS query
Posted by: Stefan Rindeskar
Date: September 03, 2009 05:31PM

If you use EXPLAIN on those two queries I would bet that your INNER JOIN query is joining in the order transcript_block->transcript while your sub-select forces MySQL to join in the order transcript->transcript_block.

Only suggestion that I have if you want to keep the persistent objects is if you can get them to: ... where exists (SELECT 1 FROM ... instead of the "SELECT * ".
But I'm not sure if it actually will improve anything.

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