Re: Matching columns in rows from two tables
От | Masaru Sugawara |
---|---|
Тема | Re: Matching columns in rows from two tables |
Дата | |
Msg-id | 20020224235923.2DA2.RK73@echna.ne.jp обсуждение исходный текст |
Ответ на | Re: Matching columns in rows from two tables (Masaru Sugawara <rk73@echna.ne.jp>) |
Список | 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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