Learn T-SQL Querying

RID Lookups

As mentioned, an RID Lookup operator represents a lookup from a non-clustered index into a heap.

The following example shows a query executed in the AdventureWorks sample database with an RID Lookup:

SELECT *FROM DatabaseLogWHERE DatabaseLogID = 5;

The query generates the following execution plan:

Notice that the results of the RID Lookup are being joined to the non-clustered index seek via a Nested Loops join operator (we will discuss join operators later in this section).