The Power of Window Functions

Aaron Cutshall

Window functions have nothing to do with the Windows operating system but provide a “window” in a data set when used in SQL queries. They are powerful, set-based methods to view data in unexpected ways. Window functions provide easy, set-based solutions to solve some common problems:

• Using running totals
• Performing operations on intervals
• Identifying data gaps and islands
• Performing aggregates without losing detail

Many people are confused by window functions and do not know how to use them properly. This session will explore window functions, how they work, and how to use them. Demonstrations with several examples will solidify how window functions can simplify queries and make them more powerful.