SELECT c.title           AS course,
       COUNT(a.id)       AS attempts,
       ROUND(AVG(a.score), 1) AS average_score
FROM courses c
JOIN quiz_attempts a ON a.course_id = c.id
WHERE a.status = 'submitted'
GROUP BY c.id, c.title
HAVING COUNT(a.id) >= 5
ORDER BY average_score DESC;