题解 | #分组过滤练习题#
分组过滤练习题
https://www.nowcoder.com/practice/ddbcedcd9600403296038ee44a172f2d
select university, round(avg(question_cnt),3) as avg_question_cnt, round(avg(answer_cnt),3) as avg_answer_cnt from user_profile group by university having avg_question_cnt < 5 or avg_answer_cnt < 20;
注意:
使用聚合函数(例如avg,)时,不可以与where共同使用,需要用having来代替where。
同时这道题要对university进行分组。