SELECT tt.user_id, user.name, tt.sum_num FROM ( SELECT * , DENSE_RANK() OVER( ORDER BY sum_num DESC ) AS rk FROM ( SELECT user_id, SUM( CASE WHEN type = 'add' THEN grade_num WHEN type = 'reduce' THEN -1 * grade_num ELSE 0 END ) AS sum_num FROM grade_info GROUP BY user_id ) AS tmp ) AS tt LEFT OUTER JOIN user ON tt.user_id = user.id WHERE rk <=1 ;