Django ORM function to sum absolute values.

django_absolute_sum.py

from django.db.models import Sum


class AbsoluteSum(Sum):
    name = 'AbsoluteSum'
    template = '%(function)s(%(absolute)s(%(expressions)s))'

    def __init__(self, expression, **extra):
        super(AbsoluteSum, self).__init__(
            expression, absolute='ABS ', output_field=IntegerField(), **extra)

    def __repr__(self):
        return "SUM(ABS(%s))".format(
            self.arg_joiner.join(str(arg) for arg in self.source_expressions)
        )

'test' table

name	amount
A	3
B	1
C	-2

'Test' model

class Test(Model):
  name=CharField(max_length=1)
  amount=IntegerField()

Usage

result = Test.objects.annotate(
  absolute_sum=AbsoluteSum('amount'),
  normal_sum=Sum('amount')
).values(
  'absolute_sum',
  'normal_sum'
)
print(str(result.query))  # SELECT (SUM(ABS(`test`.`amount`))) AS `absolute_sum`, (SUM(`test`.`amount`)) AS `normal_sum` FROM `test`

Result

print(result['absolute_sum'])  # 6
print(result['normal_sum'])  # 2

very good

Nice

still works ;d