Re: left outer join on more than 2 tables?
От | Rob Sargent |
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Тема | Re: left outer join on more than 2 tables? |
Дата | |
Msg-id | 4A38114B.7090106@gmail.com обсуждение исходный текст |
Ответ на | Re: left outer join on more than 2 tables? (Richard Broersma <richard.broersma@gmail.com>) |
Ответы |
Re: left outer join on more than 2 tables? (UNCLASSIFIED)
Re: left outer join on more than 2 tables? |
Список | pgsql-sql |
Richard Broersma wrote: > On Tue, Jun 16, 2009 at 1:59 PM, Carol > Cheung<cacheung@consumercontact.com> wrote: > >> I would like to find the counts of complaints by region and I would like all >> regions to be displayed, regardless of whether or not complaints exist for >> that region. Is left outer join what I'm looking for? >> > > SELECT R.region_name, Count(*) AS RegionComplaints > FROM Region AS R > LEFT JOIN City AS Ci > ON R.id = C.region_id > LEFT JOIN Complaint AS Cm > ON Ci.id = Cm.city_id > GROUP BY R.region_name; > > > Is there a city without a reference to region? And wouldn't you want to count(cm.id)?
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