Execution plans show you what's going on behind the scenes in SQL Server. They can provide you with a wealth of information on how your queries are being executed by SQL Server, including: [ Which indexes are being used, and where no indexes are being used at all. [ How the data is being retrieved, and joined, from the tables defi ned in your query. [ How aggregations in GROUP BY queries are put together. [ The anticipated load and the estimated cost that all these operations place upon the system. Grant Fritchey's book is the only in-depth look at how to improve your SQL query performance through careful design of execution plans. Sample chapters of the ebook have garnered stunning reviews, such as: "All I can say is WOW. This has to be the best reference I have ever seen on Execution Plans in SQL Server.

My hats off to Grant Fritchey" Jonathan Kehayias.