Message-ID: <479D3328.50903@marquesminen.com.ar>
Date: Sun, 27 Jan 2008 23:43:04 -0200
From: Martin Marques <martin@marquesminen.com.ar>
User-Agent: Thunderbird 2.0.0.9 (X11/20071115)
MIME-Version: 1.0
To: Bryce Nesbitt <bryce1@obviously.com>
CC: pgsql-sql@postgresql.org
Subject: Re: Syntax question: use of join/using with fully qualified table
 name
References: <479D2694.3090202@obviously.com>
In-Reply-To: <479D2694.3090202@obviously.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

Bryce Nesbitt escribió:
> I've got a join where a certain column name appears twice:
> 
> select username,last_name from eg_member join eg_membership using
> (member_id) join eg_account using (account_id) join eg_person using
> (person_id);
> ERROR:  common column name "person_id" appears more than once in left table
> 
> 
> My first inclination was to fully quality the table name.  Why would
> this not be acceptable syntax?
> 
> select username,last_name from eg_member join eg_membership using
> (member_id) join eg_account using (account_id) join eg_person using
> (eg_member.person_id);
> ERROR:  syntax error at or near "." at character 145

Did you read the manual?

USING (join_column [, ...])

     A clause of the form USING ( a, b, ... ) is shorthand for ON 
left_table.a = right_table.a AND left_table.b = right_table.b .... Also, 
USING implies that only one of each pair of equivalent columns will be 
included in the join output, not both.