Call now: (800) 766-1884  


 SQL Server Tips
 SQL Server Training

 SQL Server Consulting
 SQL Server Support
 SQL Server Remote DBA

 SQL Server Scripts
 Scripts Menu




  SQL Server Tips by Gama and Naughter


Update Set NULL


Set NULL requires one trigger for table [Tbl A] that will set to NULL values in the related columns from table [Tbl B].




/* * UPDATE SET NULL TO '[Tbl B]' */

IF (SELECT COUNT(*) FROM deleted, [Tbl B] WHERE (deleted. [Col A]= [Tbl B]. [Col B])) > 0

       UPDATE [Tbl B]

       SET [Tbl B]. [Col B]=NULL

       FROM [Tbl B], deleted, inserted

       WHERE deleted. [Col A]= [Tbl B].[Col B]


Let us test the trigger:


UPDATE [Tbl A] SET [col A]='2222' WHERE [col A]='1111'


It is easy to verify that the trigger worked by examining the contents of the table.

The above book excerpt is from:

Super SQL Server Systems
Turbocharge Database Performance with C++ External Procedures

ISBN: 0-9761573-2-2
Joseph Gama, P. J. Naughter


Burleson Consulting Remote DB Administration







Burleson is the America's Team

Note: The pages on this site were created as a support and training reference for use by our staff of DBA consultants.  If you find it confusing, please exit this page.

Errata?  SQL Server technology is changing and we strive to update our SQL Server support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:and include the URL for the page.

Burleson Consulting
SQL Server database support


Copyright 1996 -  2013 by Vaaltech Web Services. All rights reserved.

Hit Counter