题解 | #分组过滤练习题#
分组过滤练习题
https://www.nowcoder.com/practice/ddbcedcd9600403296038ee44a172f2d
select
university,
avg(question_cnt) avg_question_cnt,
avg(answer_cnt) avg_answer_cnt
from
user_profile
group by
university
having
avg_question_cnt <5
or avg_answer_cnt < 20;
-- 细节,当我们分组了之后,是不能用where 控制语句的 只能用having
