whtsky's wiki

https://stackoverflow.com/questions/4184558/django-query-filter-on-manytomany-is-empty

class TestModel(models.Model):
    name = models.CharField(_('set name'), max_length=200)
    manytomany = models.ManyToManyField('AnotherModel', blank=True, null=True)

TestModel.objects.filter(manytomany=None)
TestModel.objects.exclude(manytomany=None)