table1.objects.exclude(id__in= table2.objects.filter(your_condition).values_list('id', flat=True))
The exclude function works like the
Not operator you where asking for. The attribute
flat = True tells to
table2 query to return the
value_list as a one level list. So... at the end you are obtaining a list of
IDs from table2, which you are going to user to define the condition in
table1, that will be denied by the exclude function.