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Date: Sat, 19 Feb 2000 12:53:40 -0700 (MST)
From: Charles Mott <cmott@scientech.com>
To: pgsql-sql@postgresql.org
Subject: Outer Joins
Message-ID: <Pine.LNX.4.10.10002191223340.8574-100000@if.scientech.com>
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How are outer joins implemented within PostgreSQL?
I would like to do a query of the form:

    select a.x, b.y from a, b where a.x *= b.x;

The *= operator does not seem to exist.  I've been
able to devise some clumsy workarounds by creating
temporary tables:

    create table temp_table as
       select a.x, b.y from a, b where a.x = b.x;

    insert into temp_table
       select x from a
       except
           select a.x from a, b where a.x = b.x;

Outer joins are apparently quite common, but I haven't
been able to find anything on this in either the users
guide, the draft of Bruce Momjian's upcoming book or the
Deja News archives.

Charles Mott