CODEWITHSUNDEEP
djangodjango-1.8
Jon Kiparsky
Jon Kiparsky

Reputation: 7743

Annotate queryset with count of filtered related objects

In my django app (1.8) I have a model TeamMember, which has a boolean field primary_contact and a foreign key relationship to User. I would like to find the set of User objects which have no related TeamMember with primary_contact=True. (TeamMembers with primary_contact=False are fine)

I can get the count of team members easily enough:

User.objects.annotate(teammember__count=Count('teammember'))

And I can prefetch primary_contact TeamMembers easily enough as well:

User.objects.prefetch_related(Prefetch('teammember_set', queryset=.objects.filter(primary_contact=True), to_attr='primary_contacts'))

However, I have not found the incantation allowing me to filter a queryset by "Users who have no primary_contact team members".

Obviously, I would like to do this in the ORM, minimizing queries, and without raw SQL if possible.

Upvotes: 0

Views: 255

Answers (1)

Shang Wang
Shang Wang

Reputation: 25539

I might misunderstood your question but would this work?

User.objects.filter(Q(teammember__primary_contact=False) |
                    Q(teammember__isnull=True))

Upvotes: 1

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