UPDATE-no-op in SQL MERGE statement

Question

I have a table with some persistent data in it. Now when I query it, I also have a pretty complex CTE which computes the values required for the result and I need to insert miss

Answer 1

You could declare a dummy variable and set its value in the WHEN MATCHED clause.

 DECLARE @dummy int;
 ...
 MERGE
 ...
 WHEN MATCHED THEN
   UPDATE SET @dummy = 0
 ...

I believe it should be less expensive than the actual table update.