Here are the relevant clips from the MSDN documentation (emphasis is mine).
you'd have to go UPDATE Table1 , Table2 SET Table1. XXXXXX' WHERE T1= T2DECLARE @ids TABLE (id int); BEGIN TRANSACTION UPDATE Table1 SET Table1. XXXXXX' OUTPUT INTO @ids WHERE T1.field = '010008'; UPDATE Table2 SET Table2.First table ("names") Well, there is an immediate advantage in performing just a single SQL query instead of two, and I believe it is quite clear: the server will have a lighter work load.At the same time, we will have a full control on the performed operation, which will be faster and easier to maintain.(Bug #11758262, Bug #50439) See Section 22.214.171.124, “Determination of Safe and Unsafe Statements in Binary Logging”, for more information.If you access a column from the table to be updated in an expression, assignments are generally evaluated from left to right.But they can be in a batch ( a set of SQL sent to the server in one round trip) keyword.