I loved Greg’s solution to this problem, but I’d like to point that you can do the same thing directly in the admin:
from django.db import models
class CustomerAdmin(admin.ModelAdmin):
list_display = ('number_of_orders',)
def get_queryset(self, request):
# def queryset(self, request): # For Django <1.6
qs = super(CustomerAdmin, self).get_queryset(request)
# qs = super(CustomerAdmin, self).queryset(request) # For Django <1.6
qs = qs.annotate(models.Count('order'))
return qs
def number_of_orders(self, obj):
return obj.order__count
number_of_orders.admin_order_field = 'order__count'
This way you only annotate inside the admin interface. Not with every query that you do.