Expert T-SQL Window Functions in SQL Server 2019: The Hidden Secret to Fast Analytic and Reporting Queries

© Kathi Kellenberger, Clayton Groom, and Ed Pollack 2019

K. Kellenberger et al.Expert T-SQL Window Functions in SQL Server 2019https://doi.org/10.1007/978-1-4842-5197-3_3

3. Summarizing with Window Aggregates

Kathi Kellenberger¹ , Clayton Groom² and Ed Pollack³

(1)

Edwardsville, IL, USA

(2)

Smithton, IL, USA

(3)

Albany, NY, USA

 

In 2005, Microsoft introduced another type of window function to T-SQL, the window aggregates. By adding an OVER clause to an aggregate function, you can avoid the rules you must normally follow. When writing aggregate queries, you lose the details that are not included in the GROUP BY clause. Starting with SQL Server 2005, you can eliminate that restriction by adding the OVER clause. By adding OVER, you may also eliminate the ...