Clustered and nonclustered indexes share many of the same internal structures, but they're fundamentally different in nature. Watch Microsoft Certified IT Professional Jon Seigel explain the similarities and differences of clustered and nonclustered indexes, using a real-world example to show how these structures work to improve the performance of SQL queries. Blog post on primary key vs. the clustered index: http://voluntarydba.com/post/2012/10/02/The-Primary-Key-vs-The-Clustered-Index.aspx CREATE INDEX statement reference: http://technet.microsoft.com/en-us/library/ms188783.aspx ALTER INDEX statement reference: http://technet.microsoft.com/en-us/library/ms188388.aspx Index navigation internals by example: http://sqlblog.com/blogs/paul_white/archive/2011/08/09/sql-server-seeks-and-binary-search.aspx Sample index data is from the AdventureWorksLT2008R2 sample database: http://awlt2008dbscript.codeplex.com/releases/view/46169 Visit my channel for more database administration videos: https://www.youtube.com/voluntarydba Subscribe to get notified about my latest videos: https://www.youtube.com/voluntarydba?sub_confirmation=1 Read additional content on my blog: http://voluntarydba.com Follow on Twitter: https://twitter.com/voluntarydba Like on Facebook: https://facebook.com/voluntarydba