Sometimes, we want to filter objects for count annotation in Python Django.
In this article, we’ll look at how to filter objects for count annotation in Python Django.
How to filter objects for count annotation in Python Django?
To filter objects for count annotation in Python Django, we call annotate with the field argument set to the count result.
For instance, we write
from django.db.models import Q, Count
events = Event.objects.annotate(
paid_participants=Count('participants', filter=Q(participants__is_paid=True))
)
to call annotate with the paid_participants argument set to the aggregation result of getting the count of the participants field values with Count.
We call Count with filter to do the filtering when aggregating the count.
Conclusion
To filter objects for count annotation in Python Django, we call annotate with the field argument set to the count result.
