django is there a way to annotate nested object? -

i have following situation. have 3 models, post, user , friends.

class user(models.model):    name = models.charfield(max_length=100)  class friend(models.model):    user1 = models.foreignkey(user,related_name='my_friends1')    user2 = models.foreignkey(user,related_name='my_friends2')  class post(models.model):    subject = models.charfield(max_length=100)    user = models.foreignkey(user) 

every time bring users, want bring number of friends:

user.objects.filter(name__startswith='joe').annotate(fc=count('my_friends1')) 

this works fine.

however, want make work when bring users nested objects of post. i'm using there select_related minimized db calls, want like:

post.objects.filter(subject='sport').select_related('user').annotate(user__fc=count('user__my_friends1')) 

however, creates field user__fc under post, , not field fc under post.user. there way achieve functionality?

you can define custom manger models, described here , override get_queryset() method add custom column model upon query.

in order use manager reverse relation, should set base manager described in docs.

another approach this, specify manager of related model hard-coded attribute.