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Message Posted: Tue, 20 Jul 2004 @ 15:22:08 GMT

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Subj:   Re: Is there an equivalent of DUAL in Teradata
From:   Michael Larkins


Your statement is true only when the SELECT references only literal(s) while using a Set operator. However, I would have to wonder why anyone would do that when using searching for specific literal values using a WHERE clause is so much more efficent. It uses less SPOOL space and less processing power to find what is being requested (no merge processing required)

So based on efficiency, back to my original (and correct) statement, if you use a literal and any column from any table while performing a UNION, MINUS, EXCEPT or INTERSECT - the FROM is optional.


Michael Larkins
Certified Teradata Master

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