http://blogs.msdn.com/jenss/archive/2009/05/25/the-magic-about-trustable-relationships-with-null-and-not-in.aspx&#160; As a follow-up to my former post “ Why you shouldn't´trust the friendship of NULL and the (NOT) IN predicate ” I asked Paul Randal during our SQL Server Master training about the possible internal reason that the results can vary if you have NULLen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/jenss/archive/2009/05/25/the-magic-about-trustable-relationships-with-null-and-not-in.aspx#9640803Mon, 25 May 2009 22:56:56 GMT91d46819-8472-40ad-a661-2c78acb4018c:9640803Developer hearted / Relational minded : Why you shouldn't&#180;trust the friendship of NULL and the (NOT) IN predicate<p>PingBack from <a rel="nofollow" target="_new" href="http://blogs.msdn.com/jenss/archive/2009/03/07/why-you-shouldn-t-trust-the-friendship-of-null-and-the-not-in-predicate.aspx">http://blogs.msdn.com/jenss/archive/2009/03/07/why-you-shouldn-t-trust-the-friendship-of-null-and-the-not-in-predicate.aspx</a></p>