Average total sum of Django annotation sums (1.6.5)

Question

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Currently trying to get the average value of the group sum, but when I try to execute the correct set of queries, it complains about the wrong syntax

objs = MyModel.objects.filter(...).values('user', 'value')
objs = objs.annotate(sum=Sum('value')) 
# i've also tried adding `.values('sum')` to the above
objs = objs.aggregate(Avg('sum')) # whines here

Is there a way to do this without discarding SQL? Desired SQL Row

SELECT AVG(`sum`) as `avg` FROM ( 
    SELECT SUM(`appname_mymodel`.`value`) AS `sum`
    FROM `appname_mymodel` 
    GROUP BY 
        `appname_mymodel`.`user_id`, `appname_mymodel`.`value`
) as subquery ORDER BY NULL;

Not sure django works well with subqueries.

Here is the error message:

ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM (SELECT SUM(`appname_mymodel`.`value`) AS `sum` FROM `appname_' at line 1")

Django version is 1.6.5

MySQL Version - 5.5

Notes:

• If I omitted values(group by), it works fine (i.e.objs.filter(...).annotate(...).aggregate(...)
• The following example is sufficient as a fully reproducible example.

Model:

# Create your models here.

class UserProfile(models.Model):
    name = models.CharField(max_length=200)

class OtherFK(models.Model):
    name = models.CharField(max_length=200)

class MyModel(models.Model):
    # Happens if value is CharField or IntegerField
    value = models.CharField(max_length=200, blank=True, null=True)
    date = models.DateField()
    user = models.ForeignKey(UserProfile)
    other_fk = models.ForeignKey(OtherFK)

Example:

>>> from app_name.models import UserProfile, OtherFK, MyModel
>>> up = UserProfile.objects.create(name="test")
>>> fk = OtherFK.objects.create(name="test")
>>> v1 = MyModel.objects.create(user=up, other_fk=fk, value="12", date="2015-10-01")
>>> v2 = MyModel.objects.create(user=up, other_fk=fk, value="13", date="2015-10-02")
>>> from django.db.models import Sum,Avg
>>> MyModel.objects.all().values("user").distinct().annotate(sum=Sum("value")).aggregate(Avg('sum'))
ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM (SELECT DISTINCT `app_name_mymodel`.`user_id` AS `user_id`, SUM(`app_name_m' at line 1")
>>> MyModel.objects.all().values("user").distinct().annotate(sum=Sum("value"))
[{'sum': 25.0, 'user': 1L}]
>>> print MyModel.objects.all().values("user").distinct().annotate(sum=Sum("value")).query
SELECT DISTINCT `app_name_mymodel`.`user_id`, SUM(`app_name_mymodel`.`value`) AS `sum` FROM `app_name_mymodel` GROUP BY `app_name_mymodel`.`user_id` ORDER BY NULL

Answer 1

, Django 1.6, 1.7+,

python.

Answer 2

, , , , :

MyModel.objects.filter(...).values('user__id').distinct().annotate(sum=Sum('value')).aggregate(Avg('sum'))