We’re happy to announce the availability of Microsoft® SQL Server® 2012 High-Performance T-SQL Using Window Functions (ISBN: 9780735658363; 244 pages), by Itzik Ben-Gan! As Itzik explains, “Window functions are functions applied to sets of rows defined by a clause called OVER. They are used mainly for analytical purposes allowing you to calculate running totals, calculate moving averages, identify gaps and islands in your data, and perform many other computations. These functions are based on an amazingly profound concept in standard SQL (which is both an ISO and ANSI standard)—the concept of windowing . The idea behind this concept is to allow you to apply various calculations to a set, or window , of rows and return a single value. Window functions can help to ...read more