Common table expressions (CTEs), a new T-SQL feature in SQL Server 2005 (formerly code-named Yukon), give you expressive powers for writing T-SQL queries to manipulate hierarchies easily and efficiently. Some major advantages of CTEs are that they're ANSI SQL-99 compliant, they let you write shorter code than ever to manipulate hierarchies, and their internal implementation uses set-based queries rather than cursors and temporary tables. Last month, in "Get in the Loop with CTEs" (InstantDoc ID ...