Using OpenDB, we need to find all active courses and their instructors of a given quarter/semester that have no grades in their Grade Center. This must exclude non-credit courses (having course numbers containing 'X') as well as child sections of a merge. What would be the best way to do this? I have tried looking at whether the instructor visited the Grade Center tool via the activity_accumulator as well as finding courses not associated with any gradebook_log entries. Both of these methods aren't providing the results we need.