The Lonely Count

Window Functions in SQL

SQL's windowing functions are surprisingly versatile, and allow us to cut out all those self-joins and explicit cursors. Joe Celko explains how they are used, and shows a few tricks such as calculating deltas in a time series, and filling in gaps.

Calculating Values within a Rolling Window in Transact SQL

Before the SQL Window functions were implemented, it was tricky to calculate rolling totals or moving averages efficiently in SQL Server. There are now a number of techniques, but which has the best performance? Dwain Camps gets out the metaphorical stopwatch.

Window Functions in SQL Server: Part 3: Questions of Performance

A SQL expression may look elegant on the page but it is only valuable if its performance is good. Do window functions run quicker than their conventional equivalent code? Fabiano Amorim gives a definitive answer.

Window Functions in SQL Server: Part 2 - The Frame

Fabiano Amorim continues his introduction to SQL Server's implementation of the window functions by giving a history of what got implemented and when, and explaining the concept of the 'Frame' in a window function, with plenty of examples.