[Fixed]-Django: how to pass **kwarg to annotate()

Simplify..

from django.db.models import Avg, Count, Sum
# let Fname has the name of the field to sum on, set by a user input
FName='size' 
data=Department.objects.annotate(total_size=Sum(FName))

Since FName is a string, you don;t need to wrap it with quotes. If you needed tto run a different function, say avg etc…

from django.db.models import Avg, Count, Sum
# let Fname has the name of the field to sum on, set by a user input
FName='size' 
function_t = Sum # or Avg, or Count
data=Department.objects.annotate(total_size=function_t(FName))

I hope this helps you get down the path

For those who really wanted to pass a kwarg to annotate probably ’cause it is defined dinamically you have to do the following:

annotate_filters = {
    'sum_foo': Count('foo', distinct=True),
}
if foo:
    annotate_filters['sum_foo'] = Count('bar', distinct=True)
Foo.objects.annotate(**annotate_filters)

In this way you can manage different condition and pass them to the annotate function.

Happy coding.