How to annotate Count with a condition in a Django queryset

Question

Using Django ORM, can one do something like queryset.objects.annotate(Count(\'queryset_objects\', gte=VALUE)). Catch my drift?

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Here\'s a quick ex

Answer 1

For django >= 2.0 you can use Conditional aggregation with a filter argument in the aggregate functions:

from datetime import timedelta
from django.utils import timezone
from django.db.models import Count, Q # need import

Article.objects.annotate(
    numviews=Count(
        'readership__reader__id', 
        filter=Q(readership__what_time__gt=timezone.now() - timedelta(minutes=30)), 
        distinct=True
    )
)