Thursday, May 31, 2012

What is the query processing order at SQL Server?

Does SQL Server execute the query from top to bottom, starting with the SELECT clause and working its way down? You might think that, but that is not how a query is processed in SQL Server at all. SQL Server logically processes a query in the following order:


(8) SELECT
(9) TOP
(1) FROM
(3) JOIN
(2) ON
(4) WHERE
(5) GROUP BY
(6) WITH
(7) HAVING
(10) ORDER BY

:-)




I collect this information from book Wrox Professional LINQ