Hi David,

As you know, SQL is declarative language and as such describes only what result you want not how to get it. It's up to query processor (QP) to build appropriate execution plan. The SQL server QP is smart enough in simple cases to merge those two selects into one. As I mention in my previous post, most likely it'll result in the same query execution plan as the one w/o derived table.

>
>select * from ( select ... ) doesn't result in doubled work?
>
>>There's no second query in this case. As I mentioned in my other post, the execution plan for such query in most cases would be the same as with your suggestion.