Opened 10 years ago
Last modified 9 years ago
#24385 closed Bug
Problem with aggregate(Sum()) — at Initial Version
| Reported by: | Mark | Owned by: | nobody |
|---|---|---|---|
| Component: | Database layer (models, ORM) | Version: | 1.7 |
| Severity: | Normal | Keywords: | |
| Cc: | Ed Henderson | Triage Stage: | Ready for checkin |
| Has patch: | yes | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
Hello,
I setup a minimal project here: https://github.com/mcagl/minimal_django_sum_test to demonstrate the problem.
I'm working with Django 1.6.x and I noticed something that I don't understand.
As you can see from the github repository, I have a Tag model and a Row model with a m2m towards Tag and a DecimalField called amount.
If I filter Row objects for more than one Tag, and there is/are Row objects that have more than one Tag among the one filtered by, Sum('amount') counts it/them once per Tag, even if I use distinct().
Please note also that I assert, in the test, that the filtered queryset is composed by three Row objects, as expected, but the next assert fails, with 40 != 30.
I added a test that instead of aggregate(Sum('amount')) does sum([x.amount for x in rows]) which passes.
Is this a bug in Sum() or am I missing something?
Kind regards,
Mark