Itzik Ben-Gan 
Microsoft SQL Server 2012 T-SQL Fundamentals [EPUB ebook] 

Apply powerful window functions in T-SQL-and increase the performance and speed of your queries Optimize your queries-and obtain simple and elegant solutions to a variety of problems-using window functions in Transact-SQL. Led by T-SQL expert Itzik Ben-Gan, you’ll learn how to apply calculations against sets of rows in a flexible, clear, and efficient manner. Ideal whether you’re a database administrator or developer, this practical guide demonstrates ways to use more than a dozen T-SQL querying solutions to address common business tasks. Discover how to: Go beyond traditional query approaches to express set calculations more efficiently Delve into ordered set functions such as rank, distribution, and offset Implement hypothetical set and inverse distribution functions in standard SQL Use strategies for improving sequencing, paging, filtering, and pivoting Increase query speed using partitioning, ordering, and coverage indexing Apply new optimization iterators such as Window Spool Handle common issues such as running totals, intervals, medians, and gaps