tony rogerson (5/12/2009)
Using non-deterministic functions like ROW_NUMBER and NEWID need to be done carefully - my blog article: http://sqlblogcasts.com/blogs/tonyrogerson/archive/2008/06/12/bug-in-inline-expansion-of-non-deterministic-functions-in-derived-tables-and-cte-s-causes-incorrect-results.aspx explains the serious bug that exists in SQL Server 2005 with using them.
Afraid that I do not understand this. AFAIK, CTEs are table expressions like non-indexed views. If you write them non-deterministically (which is what you do in your blog article), then they return non-deterministic results. And if you reference a non-deterministic table expression multiple times, you are not guaranteed to get the same results. That's straight ANSI SQL to the best of my knowledge and I see no bug in Transact-SQL demonstrated here.
And as far as ROW_NUMBER() it only returns non-deterministic results if the OVER clause parameters are non-deterministic. If you use a deterministic ORDER BY (which also requires that the column set is uniquely orderable), then you will get deterministic results.
All this really demonstrates is that if you input non-deterministic expressions without instantiating them, then you will get non-deterministic results back. Garbage In, Garbage Out.
[font="Times New Roman"]-- RBarryYoung[/font], [font="Times New Roman"] (302)375-0451[/font] blog: MovingSQL.com, Twitter: @RBarryYoung[font="Arial Black"]
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