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Message Posted: Tue, 11 Oct 2005 @ 21:37:50 GMT

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Since you posted without any reference as to who you are or who you work for and you didn't state as much, I cannot assume that you are using RI or that your column is set up as NOT NULL. If you are not using RI or allow nulls than there is a chance that some of the rows being aggregated would not match in the join step. Therefore, non-matching rows would have gone into the aggregation when they should not have been part of that processing. Likewise, your query did not appear to be eliminating null values - so I did not assume that it did anything of the sort.

You know what they say when you ASS-U-ME too much.

Hope this helps you understand the meaning behind my observation of the posted query and the pondering about doing aggregation before the join.

Regards,

Michael Larkins
Certified Teradata Master
Certified Teradata SQL Instructor

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