Removing old quiz results from your moodle course

Sometimes, quiz scores are left over in a course, even after the enrollment(s) are removed.  They are like ghost attempts.  They confuse the user and the teacher, especially if the teacher is new to the course.  It is not my intent to do this, leave data in a course.  When new courses are deployed each fall, they should be void of student data.  But, our process is not perfect and sometimes courses are not backup up properly, properly = with no data option. 

Since I caught this before any new students started taking quizzes or commenting in forums, I am able to remove the attempts and comments using the Course Reset option

The Reset option allows you to chose between the big three, quizzes, forums and assignments.

If there had been data from current students in one of the activities, I would not have been able to do this en-masse and would have done one at a time.

My other option is to use SQL in the DB directly.  That is a little more risky than updating things in moodle directly.

The SQL I use to remove old quiz attempts from a course

EDIT `dbname`.`mdl_quiz` where course = xxx;

// get quiz ids for use in attempts query below

 EDIT `dbname`.`mdl_quiz_attempts` where quiz = xxxx;

With that result set I can remove the records.