题解 | #分组排序练习题#
分组排序练习题
http://www.nowcoder.com/practice/e00bbac732cb4b6bbc62a52b930cb15e
*group by 分组； avg 平均数； order by 排序；
select university,avg(question_cnt) as avg_question_cmt from user_profile group by university order by avg_question_cmt
