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Join question

From: "Edward W(dot) Rouse" <erouse(at)comsquared(dot)com>
To: <pgsql-sql(at)postgresql(dot)org>
Subject: Join question
Date: 2008-08-15 16:48:10
Message-ID: 04b101c8fef6$b3c87d50$1b5977f0$@com (view raw, whole thread or download thread mbox)
Lists: pgsql-sql
I have 2 tables, both have a user column. I am currently using a left join
from table a to table b because I need to show all users from table a even
those not having an entry in table b. The problem is I also have to include
items from table b with that have a null user. There are some other criteria
as well that are simple where clause filters. So as an example:


Table a:


A    | emp1

B    | emp1

B    | emp2

B    | emp3

C    | emp2


Table b:


A   |emp1|red

A   |emp1|blue

A   |null|pink

A   |null|orange

B   |emp1|red

B   |emp3|red

B   |null|silver

C   |emp2|avacado


If I:


select org, user, count(total)

from a left join b

on ( = and a.user = b.user)

where = 'A'

group by, a.user

order by, a.user


I get:



A    |emp1|2

A    |emp2|0

A    |emp3|0


But what I need is:


A    |emp1|2

A    |emp2|0

A    |emp3|0

A    |null|2



Edward W. Rouse


pgsql-sql by date

Next:From: Edward W. RouseDate: 2008-08-15 17:09:20
Subject: Re: Join question
Previous:From: Emi LuDate: 2008-08-15 13:32:32
Subject: Re: Check a column value not in Array.

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