Re: Matching columns in rows from two tables

On Sat, 23 Feb 2002 08:03:19 -0800
Richard Emberson <emberson(at)phc(dot)net> wrote:

> Thank you very much for your help. I managed to create a query with only two select
> statements
> and none of the selects are inner-selects:
>
> SELECT group_set_id, count(*) FROM group_sets , membership
> WHERE membership.user_id = <<input parameter>>
> AND membership.group_id = group_sets.group_id
> GROUP BY group_set_id
> INTERSECT
> SELECT group_set_id, count(*) FROM group_sets
> GROUP BY group_set_id;
>
> There may still be a better (better performance) query,

Quite so. I would think it's probably one of the best way. Practically,
I found my query including "where exists/not exists" is awfully slow if there
are about 1000+ rows.

> but, again, this is the
> best I could
> come up with.
>
> Thanks.
>
> Richard
>
> > On Wed, 20 Feb 2002 13:51:12 -0800
> > Richard Emberson <emberson(at)phc(dot)net> wrote:
> >
> > > I have the following tables:
> > >
> >
> > ...
> >
> > > -- a group set is a set of one or more groups
> > > CREATE TABLE group_sets (

Regards,
Masaru Sugawara