Django: use custom methods for queryset values()

Question

I am trying to use a custom method from a model as field in value method of QuerySet object.

The model:

class MyModel(models.Model):
    field1
    field2
    field3
    ...

    def custom_method(self):
        return 'somestring'

In another module, I am trying this:

MyModel.objects.all().values('field1', 'field2', 'custom_method').annotate(field3Tot= Sum('field3'))

I need to group the sum by field1, field2 and the custom_method. Is this possible or I have to use only "real" fields like field1...?

Answer 1

You can't.
values() return resultset as per fields passed into it for that model. It will not work if if you will pass any custom methods.