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.