test sql query

SELECT
 a.user_id  AS ID,
 a.first_name  AS first_name,
 a.last_name  AS last_name,
 AVG(b.correct)   AS average_correct,
 MAX(b.taken_time)  AS taken_time
 FROM `user` a
 LEFT JOIN test_result b ON a.user_id = b.user_id
 GROUP BY a.user_id ORDER BY a.user_id ASC