题解 | #SQL类别高难度试卷得分的截断平均值#

SELECT i.tag, i.difficulty, 
       ROUND(
             (SUM(r.score)-MAX(r.score)-MIN(r.score))/
             (COUNT(r.score)-2)
        ,1) AS clip_avg_score
FROM exam_record AS r
LEFT JOIN examination_info AS i 
ON r.exam_id=i.exam_id
GROUP BY i.tag, i.difficulty
HAVING i.tag='SQL' AND i.difficulty='hard'
;