1054 - Unknown column 'teacher_instruments.instrument' in 'on clause'
SELECT teacher_instruments_list.instrument_class, Count(teacher_instruments.teacher_id) AS prodcount FROM teacher_instruments_list INNER JOIN (teacher_info INNER JOIN teacher_instruments ON teacher_info.teacher_id = teacher_instruments.teacher_id) ON teacher_instruments_list.instrument_id = teacher_instruments.instrument GROUP BY teacher_instruments_list.instrument_class
