From wweng@kencast.com Thu May 30 17:16:18 2002 Received: from localhost.localdomain (postgresql.org [64.49.215.8]) by localhost (Postfix) with ESMTP id DC63E475F7C for ; Thu, 30 May 2002 13:16:18 -0400 (EDT) Received: from mta4.snet.net (mta4.snet.net [204.60.203.76]) by postgresql.org (Postfix) with ESMTP id 3C02E4761A1 for ; Thu, 30 May 2002 13:07:23 -0400 (EDT) Received: from pop.snet.net (pop.snet.net [204.60.203.72]) by mta4.snet.net (8.12.3/8.12.3/SNET-mx-1.2/D-1.1.1.1/O-1.1.1.1) with ESMTP id g4UH7HHH015400 for ; Thu, 30 May 2002 13:07:17 -0400 (EDT) X-Originating-IP: [64.252.95.167] X-SBCIS-MTA: [pop.snet.net] Received: from [192.168.1.83] (167.95.252.64.snet.net [64.252.95.167]) by pop.snet.net (8.12.3/8.12.3/SNET-pop-1.2/D-1.1.1.1/O-1.1.1.1) with ESMTP id g4UH70UQ024373 for ; Thu, 30 May 2002 13:07:00 -0400 (EDT) Subject: question on JOIN and WHERE clause From: Wei Weng To: pgsql-sql@postgresql.org Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.3 Date: 30 May 2002 13:07:21 -0400 Message-Id: <1022778442.32670.1.camel@Monet> Mime-Version: 1.0 X-Archive-Number: 200205/313 X-Sequence-Number: 7948 Does the SQL optimizer process the JOIN first then add WHERE constraintson it or it processes the WHERE clause and JOIN at the same time? Thanks! -- Wei Weng Network Software Engineer KenCast Inc. From SHenshall@westcountrypublications.co.uk Fri May 31 08:56:26 2002 Received: from localhost.localdomain (postgresql.org [64.49.215.8]) by localhost (Postfix) with ESMTP id 7F6F5475903 for ; Fri, 31 May 2002 04:56:26 -0400 (EDT) Received: from mail_exchange.westcountrypublications.co.uk (unknown [195.171.163.135]) by postgresql.org (Postfix) with ESMTP id 950654758A5 for ; Fri, 31 May 2002 04:56:24 -0400 (EDT) Received: by MAIL_EXCHANGE with Internet Mail Service (5.5.2650.21) id ; Fri, 31 May 2002 09:50:24 +0100 Message-ID: From: "Henshall, Stuart - WCP" To: 'Wei Weng' , pgsql-sql@postgresql.org Subject: Re: question on JOIN and WHERE clause Date: Fri, 31 May 2002 09:50:23 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C20880.339C90D0" X-Archive-Number: 200205/326 X-Sequence-Number: 7961 This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C20880.339C90D0 Content-Type: text/plain; charset="iso-8859-1" I believe it pushes any clauses it can into the individual sub-plans, and anything it can't it leaves above the join. - Stuart > -----Original Message----- > From: Wei Weng [mailto:wweng@kencast.com] > Sent: 30 May 2002 18:07 > To: pgsql-sql@postgresql.org > Subject: question on JOIN and WHERE clause > > > Does the SQL optimizer process the JOIN first then add WHERE > constraintson it or it processes the WHERE clause and JOIN at the same > time? > > Thanks! > > > > -- > Wei Weng > Network Software Engineer > KenCast Inc. > > > ------_=_NextPart_001_01C20880.339C90D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: question on JOIN and WHERE clause

I believe it pushes any clauses it can into the individua= l sub-plans, and anything it can't it leaves above the join.
- Stuart

> -----Original Message-----
> From: Wei Weng [mailto:wweng@kencast.com]
> Sent: 30 May 2002 18:07
> To: pgsql-sql@postgresql.org
> Subject: question on JOIN and WHERE clause
>
>
> Does the SQL optimizer process the JOIN first then = add WHERE
> constraintson it or it processes the WHERE clause a= nd JOIN at the same
> time?
>
> Thanks!
>
>
>
> --
> Wei Weng
> Network Software Engineer
> KenCast Inc.
>
>
>

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