Why does the lookup operation have no columns listed in the output list?
The execution plan is showing a key lookup. However I am not able to identify the columns that are being looked up. The output list of the lookup operation is empty. Please help me understand what I am missing here. Thanks.
The lookup is necessary to check the condition (predicate), "ScalarString5". Whichever column this references is not available in the nonclustered index, so the query processor must look it up in the base table. It is not returned by the query, so it does not appear in the Output List.
SQLkiwi – Thank you very much for the explanation. That was exactly the issue. Adding the predicate in the included columns list fixed the lookup issue. Thanks again.