Django 多对多字段依赖于另一个多对多字段

Question

I'm creating two many-to-many fields based on same model in a single model. I would like to show only those instances in second many-to-many field which are selected in first many to many field to further apply selection. Through which approach should i handle this behaviour.

class Params(models.Model):
    name = models.CharField(max_length = 200)
    comments = Model.TextField()
    
    def __str__(self):
           return self.name

class Selection(models.Model):
    select_params = models.ManyToManyField(Params, blank=True, related_name = "selection_1")
    edit_selected_params = models.ManyToManyField(Params, blank=True, related_name = 
            "selection_from_selec_params")

Thanks and regards

Answer 1

You can use SubQuery is think:

selected = Selection.objects.filter(
    edit_selected_params__in=SubQuery(
        Selection.objects.filter(select_params__isnull=False).values_list("select_params", flat=True)
    )
)

You can see SubQuery docs