From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
To: Joseph Shraibman <jks@selectacast.net>
Cc: pgsql-sql@postgresql.org
Subject: Re: joining from multiple tables
Date: Wed, 15 Jan 2003 18:02:12 -0800 (PST)
Message-ID: <20030115180057.B97388-100000@megazone23.bigpanda.com> (raw)
In-Reply-To: <3E260E41.30107@selectacast.net>
On Wed, 15 Jan 2003, Joseph Shraibman wrote:
> select distinct n.thekey, n.val, t.txt FROM num_tab n LEFT JOIN txt_tab t ON n.thekey =
> t.thekey
> WHERE n.thekey < 5 AND t.class = class_tab.tkey AND n.class = class_tab.class;
> produces:
Note that the above uses the non-standard postgres behavior of adding from
clauses, it's not technically valid SQL.
> thekey | val | txt
> --------+-----+------
> 2 | 2 | two
> 4 | 4 | four
> ... which is not what we want, because 1,3, and 5 aren't included, but:
>
> select distinct n.thekey, n.val, t.txt FROM num_tab n LEFT JOIN txt_tab t ON n.thekey =
> t.thekey AND t.class = class_tab.tkey AND n.class = class_tab.class
> WHERE n.thekey < 5;
> produces:
> NOTICE: Adding missing FROM-clause entry for table "class_tab"
> ERROR: JOIN/ON clause refers to "class_tab", which is not part of JOIN
>
> So how do I do this?
I think you want something like:
select distinct n.thekey, n.val, t.txt FROM class_tab JOIN num_tab n
using (class) LEFT JOIN txt_tab t on (t.thekey=n.thekey and t.class =
class_tab.tkey);
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To: pgsql-sql@postgresql.org
Cc: sszabo@megazone23.bigpanda.com, jks@selectacast.net
Subject: Re: joining from multiple tables
In-Reply-To: <20030115180057.B97388-100000@megazone23.bigpanda.com>
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