题解 | #分组计算练习题#

select
    gender,university,#这两项信息只需要查询，无计算
    count(device_id) as user_num,
    avg(active_days_within_30) as avg_activate_days,
    avg(question_cnt) as avg_question_cnt#这三项需要进行相应的处理
from user_profile
group by gender,university#最后以学校和性别来分组