>Of course, no problem will be created if the expression is evaluated twice. I was just thinking in terms of speed of execution. But all in all a few extra seconds does not matter much. And I am not sure the derived table will make the query executed faster. Although it is nice to know how to do it. Thank you very much.
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I found no speed degradation in using derived tables.
If it's not broken, fix it until it is.
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