Thanks for your support. I like your query but there's a problem.

I didn't execute your query yet because I didn't find place to put WHERE clause in UPDATE statement and...

Isn't there any other way without creating temporary table i.e. using new features in SQL 2005/8 CTE etc.

Thanks for your response.

I know about the identity field, but I have to update serial number only for selected records and its not a primary key field.

Following query can...