Thanks Noel and Grant,

I looked at the Execution plan and it was identical.

I still wonder why would Microsoft's EF engine create queries like this and is there any memory related performance issues for the subquery or any benefit with these approaches.

I had seen really complicated queries generated by EF for simple SUM/Average functions. It is just not clear why they do that. But still they is very negligible performance difference.

Thanks,

Nachi