django admin enable sorting for calculated fields

It isn’t possible to order by the result of the

calculated_total

method.

However, you can set the default ordering for your model admin by overriding
the

get_queryset

method for your model admin, and ordering by an
expression that calculates the same thing.

class OrderModelAdmin(admin.ModelAdmin):    ...    def get_queryset(self, request):        qs = super(OrderModelAdmin, self).get_queryset(request)        qs = qs.order_by(F('cost')*F('quantity'))        return qs

A similar approach is to annotate the queryset with the total, and then order
by that field. Assuming that cost is a

DecimalField

and quantity is an

IntegerField

, you need to use

expressionWrapper

to set the output field.
See the docs on Using F() with
annotations for more info.

I don’t think it’s possible to use

total

directly in

list_display

.
However, you can alter your

calculated_total

method to access the annotated
field. We set

calculated_total.admin_order_field = 'total'

so that the
Django admin allows you to sort on that column by clicking on it.

from django.db.models import F, expressionWrapper, DecimalFieldclass OrderModelAdmin(admin.ModelAdmin):    list_display = ['name', 'number', 'price', 'calculated_total']    def calculated_total(self, obj):        return obj.total    calculated_total.admin_order_field = 'total'    def get_queryset(self, request):        qs = super(OrderModelAdmin, self).get_queryset(request)        qs = qs.annotate(total=expressionWrapper(F('cost')*F('quantity'), output_field=DecimalField())).order_by('total')        return qs