django-mptt count items in add_related_count?

Question

How to add filter(is_public=True) to Question?

Category.objects.add_related_count(
  Category.objects.filter(is_public=True), 
  Question,
  'category',
  'question_counts',
  cumulative=True)

Answer 1

You can use the extra_filters=… parameter of the .add_related_count(…) method [Django-doc]:

Category.objects.add_related_count(
    Category.objects.filter(is_public=True), 
    Question,
    'category',
    'question_counts',
    cumulative=True,
    extra_filters={'is_public': True}
)