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Re: Performance problem with outer join
Posted by: Peter Brawley
Date: July 11, 2014 09:26AM

A left join pretty much forces a table scan on the left table. If 2 secs is too slow, and assuming you've optimised the MySQL instance for InnoDB, it might be time to institute & maintain a results table for this query (and related queries). if that seems overkill, you could at least obviate the need for left join by maintaining `accounts` reporting columns that are 0 when the child table has no matching rows.

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