Django: get subset of a model with at least one related model

Question

class Category(models.Model):
    # fields

class Product(models.Model):
     category = models.ForeignKey(Category)
     # fields

Assuming that not all the categories have at least a product,

how i can get all the categories that have at least one product associated?

Is there a way to do this with Django querysets?

Answer 1

You should be able to filter on the category. You want to find the Category's where the product isn't null right?:

Category.objects.filter(product_set__isnull=False).distinct()