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Message Posted: Thu, 17 Feb 2005 @ 10:43:12 GMT
Clever Sybase seems to avoid the problem altogether by not allowing multi-column expressions with IN / NOT IN subqueries.
In Teradata, multi-column expressions are convenient to use in this context but it looks like a must to make sure that all the columns in the subquery are non-nullable. Dieter's example is just another good argument for this rule of thumb.
I did not want to miss the Newport '58 documentary last night and had to shut down the PC pretty quickly after rerunning your script on Oracle so I did not even have a chance to analyze the results after I saw they were the same. Thanks for the clarification. It was useful to go through the example again this morning. Your point is very clear now.
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