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anbesivam · Beginner Joined: 09 Aug 2006 Posts: 66 Topics: 14

Hi,

I am getting 1000 records from 4 tables and I need to update perticular column in the 4th table.

For example, I am getting results from Table A, B, C & D using Joins and based on conditions.

kolusu · Posted: Fri Jul 15, 2011 12:20 pm Post subject:

anbesivam,

Show us the select statement of joining the 4 tables and how you are getting the results. Do you need the 4 columns or your primary goal is to update the COL4 ?

Kolusu

CZerfas · Intermediate Joined: 31 Jan 2003 Posts: 211 Topics: 8

The main problem with the update statement is, that you don't have a FROM clause where you could list more than one table.

That means, that in case of the need of accessing more than one table, you have to put these into subselects (EXIST queries) within the WHERE clause of your UPDATE statement. That doesn't make your statement more readable but gives you the desired results.

regards
Christian

GuyC · Supermod Joined: 27 May 2011 Posts: 35 Topics: 0

in other words, use a correlated subquery:

anbesivam · Beginner Joined: 09 Aug 2006 Posts: 66 Topics: 14

Thank you very much all of you for the detailed useful reply.

As the update query getting really complecated, we added some selection criteria to reduce the 4th table's results to less than 50 records and manually updated the dates.