python - CartQuantity matching query does not exist ERROR

Question

Hi I'm trying to get the newest/latest number in a query set:

I use this codeline for that:

CartQuantity.objects.filter(customer=customer).values_list('cquantity', flat=True).get(pk=-1)

This is how the queryset looks like:

<bound method QuerySet.last of <QuerySet [4, 4, 4, 2, 4, 4, 5, 6, 5, 14, 10, 12]>>  # need last number(12)

I tried the code above but I get an Error message:

store.models.CartQuantity.DoesNotExist: CartQuantity matching query does not exist.

This is my models:

class CartQuantity(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, blank=True, null=True)
    cquantity = models.IntegerField(default=0, null=True, blank=True)

Does anyone know how to fix the error or another way of getting the newest number(in this case number 12 in the query set)?

question from:https://stackoverflow.com/questions/66053178/cartquantity-matching-query-does-not-exist-error

Answer 1

CartQuantity.objects.filter(customer=customer).values_list('cquantity', flat=True)[-1]

or

CartQuantity.objects.filter(customer=customer).values_list('cquantity', flat=True).last()

or

CartQuantity.objects.filter(customer=customer).values_list('cquantity', flat=True).reverse()[0]