Update one Table from Another in a Transaction

This SQL slab shows how to update one SQL table from another, wrapped up in a nice, juicy transaction.

BEGIN TRANSACTION
    UPDATE SomeTable
    SET SomeField = T2.SomeField
    FROM SomeTable T1
    INNER JOIN SomeOtherTable T2 ON T1.CustNbr =  T2.CustNbr
 
    SELECT * FROM SomeTable
 
ROLLBACK TRANSACTION
COMMIT TRANSACTION