select ei.tag,ei.difficulty,round((sum(score)-max(score)-min(score))/(count(score)-2),1) clip_avg_score from examination_info ei join exam_record er on ei.exam_id = er.exam_id where ei.tag = 'SQL' and ei.difficulty = 'hard';

select ei.tag,ei.difficulty,round((sum(score)-max(score)-min(score))/(count(score)-2),1) clip_avg_score from examination_info ei join exam_record er on ei.exam_id = er.exam_id where ei.tag = 'SQL' and ei.difficulty = 'hard';