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Message-ID: <4A38114B.7090106@gmail.com>
Date: Tue, 16 Jun 2009 15:40:27 -0600
From: Rob Sargent <robjsargent@gmail.com>
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To: pgsql-sql@postgresql.org
Subject: Re: left outer join on more than 2 tables?
References: <4A3807CF.90109@consumercontact.com>
	<396486430906161425i1cb7949enff5443cc2043805a@mail.gmail.com>
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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)?