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Message Posted: Thu, 06 Dec 2002 @ 02:31:10 GMT

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Teradata always projects out unneeded columns at every step in the plan to minimize the number of bytes moving and/or going into spool. Each successive spool could end up with fewer columns as the need for columns goes away once qualification is performed (unless they ar required in the result set of course). Note that this is one good reason not to use SELECT * unless you really mean it - if you don't need the columns in the result, don't select them and the query gets more efficient.

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