题解 | #分组计算练习题#

--主要是对学校和性别进行分组 ，使用 group by 注意：多个分组用 英文 , 隔开，统计用 count(),平均计算用 avg()
select gender,university,
count(gender) as usr_num,
avg(active_days_within_30) as avg_active_day,
avg(question_cnt) as avg_question_cnt
from user_profile
group by university,gender