Re: left join optimization

[Nick Roper]

Hi,

One thing that would be useful is to use the 'EXPLAIN' statment to see how the optimiser is using indexes etc:

EXPLAIN SELECT etc....

Then post the output (you can use \G at the end ofthe statement to force the output into more readable layout)

Maybe you could also post the output of SHOW CREATE TABLE... for each of the three tables.

There is an article that discusses left join optimisation at:

http://dev.mysql.com/doc/mysql/en/LEFT_JOIN_optimization.html


--
Nick Roper