You execute the following code:
The execution plan for the query is shown in the exhibit. (Click the Exhibit button.)
You need to prevent the key lookup.
What should you modify?
More than one answer choice may achieve the goal. Select the BEST answer.
A.
Option A
B.
Option B
C.
Option C
D.
Option D
how about A ?
You do not need GroupName for any filter or sort, so it is enought to include this column. (Including is easier when maintaining the data respectively the index)
Neither A nor C seem to be correct. C looks closer but optimizer will still have to go to cluster for DepartmentID. Right?
I believe any nonclustered index implicitly includes the index columns of the clustered index (or RID of a heap) as it uses that to do the key lookup. So no need to explicitly include the cluster index columns.
No chintu, because when a table is clustered all index has implicit the column(s) that use to clustered the table in include on index.