Re: Accelerating subqueries

----- Original Message -----
From: "Fabrice Scemama" <fabrices@ximmo.ftd.fr>
To: <pgsql-general@hub.org>
Sent: Thursday, April 06, 2000 4:03 PM
Subject: [GENERAL] Accelerating subqueries


> Hi fellow PostgreSQL users.
>
> Here's a query:
>
> DELETE FROM Annonces WHERE Id_Ag IN
> (
>     SELECT Id FROM Installs
>     WHERE Si_Compte_Actif = 'f'
> );
>

DELETE FROM Annonces WHERE EXISTS (SELECT Id FROM Installs WHERE
Si_Compte_Actif ='f' AND Installs.Id=Annonces.Id_Ag);

ought to be a lot faster if you have indices on all concerned fields.

But this should be faster still;

DELETE FROM Annonces WHERE Annonces.Id_Ag=Installs.Id AND
Installs.Si_Compte_Actif='f';

Yours,
Moray