Re: Matching columns in rows from two tables - Mailing list pgsql-sql

From Masaru Sugawara
Subject Re: Matching columns in rows from two tables
Date
Msg-id 20020224235923.2DA2.RK73@echna.ne.jp
Whole thread Raw
In response to Re: Matching columns in rows from two tables  (Masaru Sugawara <rk73@echna.ne.jp>)
List pgsql-sql
On Sat, 23 Feb 2002 08:03:19 -0800
Richard Emberson <emberson@phc.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 thereare 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@phc.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



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