Calculate the Days Between First and Last Orders

An Intro to SQL Window Functions

Learn about some window function basics in T-SQL

What’s the Difference Between PERCENT_RANK and CUME_DIST?

Learn a bit about the different results you get from the PERCENT_RANK and CUME_DIST aggregate functions.

Christmas 2018 Trivia

Introduction to T-SQL Window Functions

T-SQL window functions were introduced in 2005 with more functionality added in 2012. Many database professionals are not aware of these useful functions. In this article, Kathi Kellenberger provides a quick overview of just what a window function is as well as examples of each type of function.

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.