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) as avg_question_cnt, avg(answer_cnt) as avg_answer_cnt from user_profile group by university having avg_question_cnt < 5 or avg_answer_cnt < 20; -- 按university聚合后,使用having,不能使用where 才能使用 统计的平均值