Itzik Ben-Gan & Steve Kass 
Inside Microsoft SQL Server 2008 T-SQL Querying [EPUB ebook] 

Tackle the toughest set-based querying and query tuning problems-guided by an author team with in-depth, inside knowledge of T-SQL. Deepen your understanding of architecture and internals-and gain practical approaches and advanced techniques to optimize your code’s performance. Discover how to: Move from procedural programming to the language of sets and logic Optimize query tuning with a top-down methodology Assess algorithmic complexity to predict performance Compare data-aggregation techniques, including new grouping sets Manage data modification-insert, delete, update, merge-for performance Write more efficient queries against partitioned tables Work with graphs, trees, hierarchies, and recursive queries Plus-Use pure-logic puzzles to sharpen your problem-solving skills