Mysql: Perform of NOT EXISTS. Is it possible to improve permofance?

Posted by petRUShka on Stack Overflow See other posts from Stack Overflow or by petRUShka
Published on 2010-06-07T21:33:31Z Indexed on 2010/06/07 21:42 UTC
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mysql

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Performance

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not-exists

I have two tables posts and comments. Table comments have post_id attribute. I need to get all posts with type "open", for which there are no comments with type "good" and created date MAY 1.

Is it optimal to use such SQL-query:

SELECT  posts.* FROM  posts  
WHERE NOT EXISTS (
SELECT comments.id FROM comments WHERE comments.post_id = posts.id 
AND  comments.comment_type = 'good' AND 
comments.created_at BETWEEN '2010-05-01 00:00:00' AND '2010-05-01 23:59:59')

I'm not sure that NOT EXISTS is perfect construction in this situation.

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