How to undo a SQL Server UPDATE query?

Question

In SQL Server Management Studio, I did the query below.
Unfortunately, I forgot to uncomment the WHERE clause.
1647 rows were updated instead of 4.

Answer 1

Since you have a FULL backup, you can restore the backup to a different server as a database of the same name or to the same server with a different name.

Then you can just review the contents pre-update and write a SQL script to do the update.