Question

I’m writing a management command which will filter a product’s original price with suggested prices.

I have a product model which looks like :

class Suggestion(models.Model):
    ....
    price = models.IntegerField()

class Product(models.Model):
    price = models.IntegerField()
    suggestions = models.ManyToManyField(Suggestion)

I want to filter all products whose price is equal to minumum suggestion. Something should like :

Product.objects.filter(price = minumum(suggestions))

AND

I want to filter products where the suggestions contains the Product’s original price. Something should like :

Product.objects.filter(price__in = self.suggestions)

The problem is I can’t use a for-loop to look each Product’s minumum suggestion and as you guess I can’t use object’s self either, so how can I compare two fields of a model in a query ?

Answer 1

from django.db.models import F
Product.objects.filter(price__in=F('suggestions'))