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From: Richard Huxton <dev@archonet.com>
Organization: Archonet Ltd
To: ta145@yahoo.com (Trey Ackerman), pgsql-general@postgresql.org,
	pgsql-php@postgresql.org, pgsql-sql@postgresql.org
Subject: Re: looking to speed up SELECT ... LEFT JOIN query
Date: Thu, 8 Aug 2002 15:24:17 +0100
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On Wednesday 07 Aug 2002 6:03 am, Trey Ackerman wrote:
> Hi,
>
> I have a working SELECT statement using LEFT JOIN but I'm hoping
> someone can suggest something that might be a bit quicker (currently 3
> seconds for result).
>
> SELECT * FROM ((table1 LEFT JOIN table2 USING (custno)) AS j1
>          LEFT JOIN table3 USING (custno)) AS j2
>          LEFT JOIN table4 USING (custno)
>          WHERE custno=3D'$custno';
>
> The primary table is table1, the key for all tables is 'custno'.  I
> need the LEFT JOIN because any one or all of the other tables (table2,
> table3, table4) might not have corresponding data.

We'll need to see the output of an EXPLAIN / EXPLAIN ANALYSE - also could y=
ou=20
join the tables in a different order, smallest first?

- Richard Huxton