- 5. Grouping and Windowing
- from Training Kit (Exam 70-461): Querying Microsoft® SQL Server® 2012
- Publisher: Microsoft Press
- Released: December 2012
Could use the function if you wanted to create groups of sales by customer-by year, by customer overall, by year overall for example. For year overall, the customer number would be NULL. The NULL set returns the aggregate total for every potential member of the set.