Aggregate a list with SQL like expressions like group by, when, case etc.

It would be nice when you retrieve a list to summarise it with sql like language.

For example retrieve a Sales list and then summarise it with expression such as

Select Region, Product, Month, SUM(TotalSales) From Sales Group By Region, Product, Month

Which can then result in a Non persistable entity with attributes Region, Product, Month and TotalSales