Django: annotate Sum Case When depending on the status of a field

Question

In my application i need to get all transactions per day for the last 30 days.

In transactions model i have a currency field and i want to convert the value in euro if

Answer 1

We need to aggregate the query set to accomplish what you are trying.

Try using aggregate()

queryset = Transaction.objects.filter(created__gte=last_month, status=Transaction.COMPLETED).extra({"date": "date_trunc('day', created)"}).values('date').aggregate(
amount=Sum(Case(When(currency=Core.CURRENCY_EUR, then='amount'), 
                When(currency=Core.CURRENCY_USD, then=F('amount') * 0.8662), 
                When(currency=Core.CURRENCY_GBP, then=F('amount') * 1.1413), default=0, output_field=FloatField())))

for more info: aggregate()