Extracting Month from date during a query

[Eswar Subramanyam]

I am using MongoDB as underlying DB with Django.

pipeline =  {
                'price' : Sum('price'),
                'month' : ExtractMonth('dateValue'),
            }

queryset = ListingBooks.objects.values('dateValue','typeBook').annotate(**pipeline)

Unfortuantely i get a NotImplementError, as if Djongo ORM i use doesnt implement this function.

Can anyone hint me on how to keep the grouping by month at this query level without having to do it manually at the serverside or client side ?

Thank you

Es.