select gender,university
,count(device_id) as user_num
,round(avg(active_days_within_30),1) as avg_active_day
,round(avg(question_cnt),1) as avg_question_cnt
from user_profile
group by gender,university

这个题的考察点比较多。
多列分组。
聚合函数。
使用round控制小数点。