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Message Posted: Fri, 03 Dec 2004 @ 15:51:55 GMT

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Although a function like RANK will work for this, it is not a random sample. Instead, it will always return the highest values or optional the lowest values. Plus, you did not tell us which release of Teradata you are running, so here a way to get a random sampling in both V2R4 and V2R5:

     sel country_code, state_code, county_code
     from (sel country_code, state_code, county_code, csum(1,1) as randomizer
            from country_table   group by 1  qualify randomizer < 51) DerivedTable

If you have V2R5 and prefer ANSI standard SQL, you should be able to do the same thing with ROW_NUMBER.

Hope this helps,

Michael Larkins
Certified Teradata Master
Certified Teradata SQL Instructor

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