Django filter parent on base of child

i have invoice model

class Invoice(models.Model):
    name                         = models.ForeignKey('Patient', on_delete=models.CASCADE)

i have another invoice amount model which have FK of invoice

class InvoiceAmount(models.Model):
    invoice                         = models.ForeignKey('Invoice', on_delete=models.CASCADE)
    amount                          = models.IntegerField(default=0)
    is_paid                         = models.BooleanField(default=False)

i want to get invoices which have is_paid = True invoice amounts

i am using this query but it’s not working

Invoice.objects.annotate(all_paid=Exists(InvoiceAmount.objects.filter(is_paid=True, id=OuterRef('pk')))).filter(all_paid=True) 

>Solution :

You can check if there are no InvoiceAmounts with is_paid=False, so:

from django.db.models import Exists, OuterRef, Q

Invoice.objects.annotate(
    all_paid=~Exists(
        InvoiceAmount.objects.filter(~Q(is_paid=True), invoice_id=OuterRef('pk'))
    )
).filter(all_paid=True)