Re: Conditional query plans.

> update users set enabled='f',disablereason='We do not allow our
> system to be used for SPAM.' where id in (select id from users where
> loginid in (select distinct loginid from logins where
> ip='123.123.12.12'));

Would it run better as:

update users set enabled='f',disablereason='We do not allow our
system to be used for SPAM.' where id in (select distinct loginid from
logins where
ip='123.123.12.12');

Or perhaps even:

update users set enabled='f',disablereason='We do not allow our
system to be used for SPAM.' where id in (select unique id from users,logins
where
users.loginid=logins.loginid where ip='123.123.12.12');

I don't know if that helps the query plan, but it looks prettier :)