Django query where in

Two querysets is documented way of doing this. It will be one database hit anyway.

test_ids = Subject.objects.all()
result = Test.objects.filter(test_id__in=test_ids).filter([some other filtering])

DrTyrsa just about had it.

test_ids = list(TestSubjectSet.objects.all().values_list('test_id', flat=True))
result = Test.objects.filter(id__in=test_ids, test_begin_time__lt='', test_end_time__gt='')

The way Tyrsa was doing it would not give you a list of the Test ids from TestSubjectSet, but instead give you a TestSubjectSet queryset.

Also, I was confused by the test_begin_time and test_end_time fields, because you didn't mention them in your models.

Update: Used list() on the queryset, because, according to the link DrTyrsa posted, DBs "don't optimize nested querysets very well".

this worker for me:

Line.objects.filter(pk__in=[1, 2, 3])