ok, we got a join thats working to find root concepts by putting the null test in the where rather than the join
ok, we got a join thats working to find root concepts by putting the null test in the where rather than the join

aodn/vocab,julian1/vocab2,julian1/vocab,aodn/vocab,julian1/vocab2,julian1/vocab,aodn/vocab,julian1/vocab2,julian1/vocab,aodn/vocab