Microsoft® SQL Server 2012 Unleashed

The OVER Clause

The OVER clause is used in a query to determine the partitioning and ordering of a rowset before the associated window function is applied. That is, the OVER clause defines a window or user-specified set of rows within a query result set. A window function then computes a value for each row in the window. You can use the OVER clause with functions to compute aggregated values such as moving averages, cumulative aggregates, running totals, or a top N per group results.

The OVER clause can be used with the following:

Ranking functions

Aggregate functions

Analytic functions

NEXT VALUE FOR function

Let’s first take a look at using ...