题解 | 统计每个学校的答过题的用户的平均答题数
select university, round(count(*)/count(distinct s1.device_id),4) as avg_answer_cnt from user_profile s1, question_practice_detail s2 where s1.device_id=s2.device_id group by university order by university
select university, round(count(*)/count(distinct s1.device_id),4) as avg_answer_cnt from user_profile s1, question_practice_detail s2 where s1.device_id=s2.device_id group by university order by university
相关推荐