Date: Tue, 22 Aug 2006 09:59:29 -0700 (PDT)
From: Stephan Szabo <sszabo@megazone.bigpanda.com>
To: Brian Cox <bcox4982@yahoo.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: joining VIEWs
In-Reply-To: <20060822164004.88034.qmail@web39806.mail.mud.yahoo.com>
Message-ID: <20060822095739.L69038@megazone.bigpanda.com>
References: <20060822164004.88034.qmail@web39806.mail.mud.yahoo.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Tue, 22 Aug 2006, Brian Cox wrote:

> Given a view like:
>
>  create view view1 as
>  select g.id as UserGroupId, s.uid as UserId, s.time as StartTime from stats s join groups g on g.uid = s.uid
>
>  and a SELECT like:
>
>  select a.UserGroupId,b.UserGroupId from view1 a
>  full outer join view1 b on b.UserGroupId = a.UserGroupId
>  WHERE a.StartTime >= '2006-1-1' AND a.StartTime < '2007-1-1'
>    AND b.StartTime >= '2005-1-1' AND b.StartTime < '2006-1-1';
>
>  where there are 5695 rows in 2006 and 1 row in 2005, I expected to get
>  a result set of 5695 rows, but instead got only 1 row (the common row
>  in the 2 years).  This seems contrary to the definition of "full outer
>  join".  Am I missing something?

The where clause is applied after the join. If you want to filter the rows
before/during the join itself you can use subselects in the from clause or
put the additional conditions in the on condition.