When writing an SQL Merge Statement, I wanted to avoid updating rows that hadn't changed. The trick is to use EXISTS and EXCEPT The page at http://www.made2mentor.com/2013/05/writing-t-sql-merge-statements-the-right-way/ explains this well There's also a reference to Paul White's page https://www.sql.kiwi/ MERGE #Customer_New AS Target USING #Customer_Orig AS Source ON Target. CustomerNum = Source. CustomerNum WHEN MATCHED AND EXISTS ( SELECT Source. CustomerName , Source. Planet EXCEPT SELECT Target. CustomerName , Target. Planet ) THEN UPDATE SET Target. CustomerName = Source. CustomerName ,Target. Planet = Source. Planet WHEN NOT MATCHED BY TARGET THEN INSERT ( CustomerNum, CustomerName, Planet ) VALUES ( CustomerNum, Source. CustomerName , Source. Planet ) WHEN NOT MATCHED BY SOURCE THEN DELETE ;