Received: from maia.hub.org (unknown [200.46.204.183])
	by mail.postgresql.org (Postfix) with ESMTP id BF586633427
	for <pgsql-general-postgresql.org@mail.postgresql.org>;
	Mon,  1 Feb 2010 16:25:53 -0400 (AST)
Received: from mail.postgresql.org ([200.46.204.86])
	by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia,
	port 10024) with ESMTP id 51280-10
	for <pgsql-general-postgresql.org@mail.postgresql.org>;
	Mon,  1 Feb 2010 20:25:43 +0000 (UTC)
X-Greylist: delayed 05:03:26.953993 by SQLgrey-1.7.6
Received: from mail-ww0-f46.google.com (mail-ww0-f46.google.com
 [74.125.82.46])
	by mail.postgresql.org (Postfix) with ESMTP id 233BD6332A3
	for <pgsql-general@postgresql.org>;
	Mon,  1 Feb 2010 16:25:42 -0400 (AST)
Received: by wwi18 with SMTP id 18so550826wwi.19
	for <pgsql-general@postgresql.org>;
	Mon, 01 Feb 2010 12:25:41 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma;
	h=domainkey-signature:mime-version:received:in-reply-to:references
	:date:message-id:subject:from:to:cc:content-type;
	bh=vaLVfj8ZSQGBv+Z+Ckqqnwly9JidL1HvLdYe6U2f//I=;
	b=t80AOL7z5Y3qjYOVn59a1lq3r1N1gq/b2v9H7rHithWLSjdl/BZ9iXHWt6szQ3fOl8
	QP3+JJDQEB9Mo7zEi6UBf8B+dlKNosf2FrBhSb6S6CBydq17rC0QMoMACE3Zsnj/ImQS
	HoIv3Zr74SQqzzCfTdtilmaZFxnnzU0e6cr+o=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma;
	h=mime-version:in-reply-to:references:date:message-id:subject:from:to
	:cc:content-type;
	b=DjXkhisJW4hF98lhP/HiUO+HbNfmYTYbN7SuC2xyRR9eYxP8P4GwVwDOzKfz0ueZEc
	gMZ99Fy6K2c32pTV6ByKPaX5oQ9bGHd8zDsCOSR807SrO2k9rmj0DDJL/uD6i41Y5+b0
	MhkAp4mMtSt+vRoNLNj+43uo4gqIxujAJdeV0=
MIME-Version: 1.0
Received: by 10.216.88.202 with SMTP id a52mr78450wef.101.1265055941324; Mon,
	01 Feb 2010 12:25:41 -0800 (PST)
In-Reply-To: 
 <F4C27E77F7A33E4CA98C19A9DC6722A2057D815E@EXCHANGE.corp.perceptron.com>
References: <995516.81823.qm@web113717.mail.gq1.yahoo.com>
	<OF1DFE3081.6BFBD791-ON802576BD.0031A099-802576BD.00327569@shropshire.gov.uk>
	<F4C27E77F7A33E4CA98C19A9DC6722A2057D815E@EXCHANGE.corp.perceptron.com>
Date: Mon, 1 Feb 2010 13:25:41 -0700
Message-ID: <dcc563d11002011225p80b1af7ta400155584e1f1fb@mail.gmail.com>
Subject: Re: combine SQL SELECT statements into one
From: Scott Marlowe <scott.marlowe@gmail.com>
To: Igor Neyman <ineyman@perceptron.com>
Cc: Chris.Ellis@shropshire.gov.uk, neilstylz@yahoo.com,
	pgsql-general@postgresql.org
Content-Type: text/plain; charset=ISO-8859-1
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Spam-Status: No, hits=-2.599 tagged_above=-10 required=5
	tests=BAYES_00=-2.599
X-Spam-Level: 
X-Archive-Number: 201002/48
X-Sequence-Number: 158824

On Mon, Feb 1, 2010 at 12:09 PM, Igor Neyman <ineyman@perceptron.com> wrote:
> Original poster asked for the sql that will touch inventory table only
> once.
>
> Your statement (with 3 subqueries) will do it 3 times.

I'm pretty sure that starting with 8.3 the engine will collapse all
those into one seq scan internally.