Many to many and how to get a queryset from queryset

Question

I have following models:

class Product(models.Model):
    name = CharField(max_length=30)

class Store(models.Model):
    name = CharField(max_length=30)
    product = models.ManyToManyField(Product)

How to get Stores with product named product_name and also, get all the products (except the product with name product_name) ? Is it possible to make it in one query? In raw SQL it would be simple JOINs. Not sure how to implement it via Django.

Answer 1

You can actually do these things with Django due to it's lazy queryset evaluation. Django's in field lookup accepts both lists and querysets. The following will create a nested SQL code:

products = Product.objects.filter(store_set__in=stores_qs)
stores_qs = Store.objects.filter(product__name='product_name')

Here are the Django in docs.