|Subject||RE: [firebird-support] Re: IN clause - using static values vs table values|
> > Adam wrote,if you have an admin tool like IBExpert (or several others), the plan
> > A couple of hundred is OK, although it hits the index for EACH member.
> > You will have problems if you try with 1500 though.
> > It does not make sense to delete from a join. You can do
> > delete from sometable where ID in (select ID from sometable join ....)
> Adam, sorry if I keep hammering on the same point, but say I had
> 1500 items
> in my list. Would it be more efficient to use a hard coded IN
> clause where
> the index gets hit once per item, or would it be better to use the DELETE
> FROM X WHERE Y IN( SELECT ....) method.
> I would assume that firebird would have to do more work in the
> second case
> by having to generate the list that I would have supplied as part of the
> query, and in the process also generating index hits. I guess there is
> additional work involved in parsing the IN clause in the case of
> DELETE FROM
> X WHERE Y IN(1,2,3), but is it more work than in the first case?
> Thanks for your time, much appreciated
analyzer will give you chapter and verse about the index reads and query
efficiency. Test it yourself to get the full picture.