From: Rajesh Kumar Mallah <mallah@trade-india.com>
To: pgsql-sql@postgresql.org
Subject: question about visibilty while updating multiple rows .
Date: Wed, 9 Apr 2003 12:47:59 +0530
Message-ID: <200304091247.59378.mallah@trade-india.com> (raw)
Hi,
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?
for example consider following set of data rows:
+------------+-----------------------+------+----------+----------------------------------+
| profile_id | co_name | size | deletion | md5 |
+------------+-----------------------+------+----------+----------------------------------+
| 212161 | ATITH FIBRE PVT. LTD. | FL | t | edc462794427724b7d132e3b1387d69f |
| 212159 | ATITH FIBRE PVT. LTD. | 1HS | f | edc462794427724b7d132e3b1387d69f |
| 216225 | ATITH FIBRE PVT. LTD. | 1HS | f | edc462794427724b7d132e3b1387d69f |
| 216226 | ATITH FIBRE PVT. LTD. | 1HS | f | edc462794427724b7d132e3b1387d69f |
+------------+-----------------------+------+----------+----------------------------------+
begin work;
UPDATE eyp_profiles_table SET
deletion=true
WHERE
co_name='ATITH FIBRE PVT. LTD.' AND
deletion is false and
EXISTS (select * from eyp_profiles_table a where a.md5=eyp_profiles_table.md5 and
a.deletion is false and a.profile_id <> eyp_profiles_table.profile_id) ;
my original problem is to update in such a way that i get below finally (observer the deletion column)
+------------+-----------------------+------+----------+----------------------------------+
| profile_id | co_name | size | deletion | md5 |
+------------+-----------------------+------+----------+----------------------------------+
| 212161 | ATITH FIBRE PVT. LTD. | FL | t | edc462794427724b7d132e3b1387d69f |
| 212159 | ATITH FIBRE PVT. LTD. | 1HS | t | edc462794427724b7d132e3b1387d69f |
| 216225 | ATITH FIBRE PVT. LTD. | 1HS | t | edc462794427724b7d132e3b1387d69f |
| 216226 | ATITH FIBRE PVT. LTD. | 1HS | f | edc462794427724b7d132e3b1387d69f |
+------------+-----------------------+------+----------+----------------------------------+
so that only one entry per md5 record exists.
Regds
mallah.
--
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.
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To: pgsql-sql@postgresql.org
Cc: mallah@trade-india.com
Subject: Re: question about visibilty while updating multiple rows .
In-Reply-To: <200304091247.59378.mallah@trade-india.com>
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