Django - Can you use property as the field in an aggregation function?

Question

I know the short answer because I tried it. Is there any way to accomplish this though (even if only on account of a hack)?

class Ticket(models.Model):
    a         


        

Answer 1

I have a similar scenario and want exactly the same feature. I solved it trivially with the following line:

...
return sum(lt.cost for lt in self.lineitem_set)

Answer 2

No. Anything that goes through a built-in manager has to be a real field, since they only touch the database. In order to work with a property they'd have to turn every record in the table into a model, then filter through them in Python.