Re: Overhead of union versus union all

From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: Greg Stark <gsstark(at)mit(dot)edu>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, Scott Bailey <artacus(at)comcast(dot)net>, pgsql-general(at)postgresql(dot)org
Subject: Re: Overhead of union versus union all
Date: 2009-07-10 17:51:47
Message-ID: 1247248307.26589.329.camel@monkey-cat.sm.truviso.com
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On Fri, 2009-07-10 at 18:47 +0100, Greg Stark wrote:
> > -- foo has a primary key

> Well no, it's equivalent to SELECT DISTINCT * FROM foo;

I think you missed that "foo" has a primary key.

Regards,
Jeff Davis

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