Cumulative (running) sum with django orm and postgresql

Question

Is it possible to calculate the cumulative (running) sum using django\'s orm? Consider the following model:

class AModel(models.Model):
    a_number = models         


        

Answer 1

You can try to do this with Func expression.

from django.db.models import Func, Sum

AModel.objects.annotate(cumsum=Func(Sum('a_number'), template='%(expressions)s OVER (PARTITION BY %(partition_by)s)', partition_by='id')).values('id', 'cumsum').order_by('id')