[Answered ]-Django – Filter by distinct fields of a model class

by

1👍

✅

activities = Activity.objects.filter(actor__in=users).distinct('content_type', 'object_id', 'action')

If your database does not support DISTINCT ON queries, you can do the query then manually run through the objects finding distinct values:

unique_activities = []
activities = Activity.objects.filter(actor__in=users)
for activity in activities:
    unseen = True
    for unique_activity in unique_activities:
        if (activity.action == unique_activity.action and activity.content_type == unique_activity.content_type and activity.object_id == unique_activity.object_id):
            unseen = False
            break
    if unseen:
         unique_activities.append(activity)

print unique_activities
👤Daniel Robinson

1👍

This will work only with PostgreSQL:

Activity.objects.order_by('action', 'content_type_id', 'object_id', '-pub_date').distinct('action', 'content_type_id', 'object_id').filter(actor__in=actors)
👤almalki

0👍

This sounds like a greatest-per-group problem. Can you try this:

activities = Activity.objects.filter(
    id__in=Activity.objects.values('content_type') \
        .annotate(max_id=Max('id')) \
        .values_list('max_id', flat=True) \
)
👤Todor

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