From: Rajesh Kumar Mallah <mallah@trade-india.com>
Organization: Infocom Network Limited
To: Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: question about visibilty while updating multiple rows .
Date: Thu, 10 Apr 2003 10:11:19 +0530
User-Agent: KMail/1.5
Cc: pgsql-sql@postgresql.org
References: <200304091247.59378.mallah@trade-india.com>
	<7045.1049901168@sss.pgh.pa.us>
In-Reply-To: <7045.1049901168@sss.pgh.pa.us>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="utf-8"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200304101011.20087.mallah@trade-india.com>

On Wednesday 09 Apr 2003 8:42 pm, Tom Lane wrote:
> > If an update statement is affecting multiple rows of a table X ,
> > Does a subselect (selecting from X only)  inside EXISTS part of outer
> > query able to see the changes when rows are being updated one by one by
> > outer query?
>
> No, because it's part of the same query.
>
> I believe though that a user-defined function called from the update
> query would see the changes made so far.  So possibly you can fix your
> problem by pushing the EXISTS down into a SQL or plpgsql function.

Thanks for the explanation and suggestion Tom,
I did it however by using intermediate tables and distinct on().

Regds
Mallah.


>
> 			regards, tom lane
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly

-- 
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.