GroupBy - General info

May 8, 2013 at 2:37 AM
Edited May 8, 2013 at 2:40 AM

I am trying to understand the GroupBy, but the documentation is little

has somebody some example about GroupBy ?

in the example, I can see:
.GroupBy("$.Date", "$.Id", .....

why two parameters ? if only need group by date, which is the $.Id functionality ?