Left Join extremely slow (MySQL)
| From: | James Crowley | Date: | Fri, 03 Aug 2001 16:40:18 +0000 |
| Subject: | Left Join extremely slow (MySQL) | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-61154@lists.php.net to get a copy of this message | ||
Hi,
I had been using an INNER JOIN statement for a MySQL query, which
worked fine. However, my new ISP does not have the latest version of
MySQL. The version they have does not support conditions for Inner Join
statements, so I have tried switching to a Left Join instead. However,
the Left Join query takes 12.15 sec (which is obviously far too slow).
The Inner join statement, meanwhile, completed the query in 0.04. Any
idea why??
Here are the two statements (fast):
SELECT i.id, i.title, i.description FROM dir_items i INNER JOIN
dir_assoc a ON a.itemid=i.id WHERE a.parentid=59 AND a.ex=0
Here are the two statements (slow):
SELECT i.id, i.title, i.description FROM dir_items i LEFT JOIN dir_assoc
a ON a.itemid=i.id WHERE a.parentid=59 AND a.ex=0
Regards,
- James
Editor, VB Web
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