Re: Can't understand why optimizer doesn't work properly :(

[Sergey Belov]

The original query

SELECT * FROM Messages WHERE Messages.Ask IN (SELECT Ask.Ask FROM Ask WHERE Ask.DateTime<20070710)

was rewritten by documentation:

SELECT * FROM Messages WHERE EXISTS (SELECT 1 FROM Ask WHERE Ask.Ask = Messages.Ask AND Ask.DateTime<20070710)

The `Ask` table has much less rows than the `Messages` table. And there is condition in select `Ask` table. So, the rows count in select will be even less.

How can I tell optimizer, that it should first select subquery an than select outer query? I can't use JOIN syntax, because this select is a part of Insert construction.