题解 | #分组计算练习题#

方法一： select gender,university,count(*) as user_num, avg(active_days_within_30) as avg_active_day, avg(question_cnt) as avg_question_cnt from user_profile group by gender,university;

方法二： select gender,university,count() as user_num, round(sum(active_days_within_30)/count(),1) as avg_active_day, round(sum(question_cnt)/count(*),1) as avg_question_cnt from user_profile group by gender,university;