Using Django, how I can achieve this in a single query?
python,django,django-queryset,timedelta,django-aggregation
As noted in the documentation, arithmetic with a DurationField will not always work as expected in databases other than PostgreSQL. I don't know to which extend this works or doesn't work in other databases, so you'll have to try it yourself. If that works, you can use the following query:...
How to filter objects for count annotation in Django?
python,django,django-models,django-aggregation
Just discovered that Django 1.8 has new conditional expressions feature, so now we can do like this: events = Event.objects.all().annotate(paid_participants=models.Sum( models.Case( models.When(participant__is_paid=True, then=1), default=0, output_field=models.IntegerField() ))) ...
Django 1.6 + MySQL : Type Cast MySQL variable to search for Max, Avg
mysql,django,django-orm,django-aggregation
I think you must go with .raw because using .extra wont be possible here. The problem is because Django don't have .group_by the only way go group by something is to use .values and .annotate after that. (as you have done it in the first attempt) so.. why you can't...
Django aggregation over choices
yes, you can! from django.db.models import Count voting_round_instance.vote_set.values('vote') \ .annotate(count=Count('vote')).distinct() EDIT : use order_by() You may also need to make sure the default ordering does not mess up your aggregation. This is especially true when using related object managers. https://docs.djangoproject.com/en/1.8/topics/db/aggregation/#interaction-with-default-ordering-or-order-by Fields that are mentioned in the order_by() part of a...
Wrong GROUP BY field in Django annotate query
sql,django,django-models,django-orm,django-aggregation
Opened Django compiler: def collapse_group_by(self, expressions, having): # If the DB can group by primary key, then group by the primary key of # query's main model. Note that for PostgreSQL the GROUP BY clause must # include the primary key of every table, but for MySQL it is enough...