Re: left outer join on more than 2 tables? (UNCLASSIFIED)

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My problem with that is that you are counting rows per region and you have done a left jion on region. That means there will be at least one row per region even if there are 0 compliants. It might yield the same result now, but if you even have a period where a region recieves no complaints they will have a complaint count of 1 instead of 0. That is just my guess based on the logic.

-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org [mailto:pgsql-sql-owner(at)postgresql(dot)org] On Behalf Of Richard Broersma
Sent: Tuesday, June 16, 2009 3:50 PM
To: Rob Sargent
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] left outer join on more than 2 tables?

On Tue, Jun 16, 2009 at 2:40 PM, Rob Sargent<robjsargent(at)gmail(dot)com> wrote:

> Is there a city without a reference to region?

I don't know, but the OP wanted to know complaints by region.

>  And wouldn't you want to count(cm.id)?

Count(cm.id) and Count(*) produce the same result. But I like
Count(*) more since it helps to correctly express the idea that we are counting rows per group and not cm.id(s) per group.

--
Regards,
Richard Broersma Jr.

Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug

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