TB
class ModelA(models.Model):
name = models.CharField(max_length=1)
class ModelB(models.Model):
name = models.CharField(max_length=1)
class ModelAItems(models.Model):
model_a = models.ForeignKey(ModelA, on_delete=models.CASCADE, related_name='items')
model_b = models.ForeignKey(ModelB, on_delete=models.CASCADE)
нужный_мне_model_b_ид = 5
for instance_model_a in ModelA.objects.all():
items = ModelAItems.objects.filtet(model_a=instance_model_a, model_b_id=нужный_мне_model_b_ид)