题解 | #sql19分组过滤练习题#
分组过滤练习题
http://www.nowcoder.com/practice/ddbcedcd9600403296038ee44a172f2d
因为忘记having 写了个嵌套表 笑死我了
select university,avg_question_cnt, avg_answer_cnt
from
(select university,avg(question_cnt) as avg_question_cnt,avg(answer_cnt) as avg_answer_cnt
from user_profile
group by university) a
where avg_question_cnt<5 or avg_answer_cnt<20