Bonnie,
You have to weigh carefully the costs of tripling the I/O (read + write + read vs read) and forcing tempdb hits compared to the overhead of a dynamic query. And if you are the least bit curious open master.sp_rename and look at all the hoops involved in there. *g*
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>I was thinking about splitting your query into 2 steps. A regular query into a temp table and dynamic query from the temp table with calculated columns added. >
>Ah ... good idea Sergey. And while I was reading your reply and thinking about it, my co-worker pointed me to something he had found which is similar, but even better (downside is that it still involves 2 selects):
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http://www.sommarskog.se/dynamic_sql.html#columnalias>
>Basically it involves selecting into a temp table and then renaming the column(s) in the temp table and then selecting from it.