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 # 保留三位小数 from user_profile group by university # 按学校分组 having avg(question_cnt)<5 or avg(answer_cnt)<20; # 注:where 从记录中法过滤出某一条记录 # having 可以从一组组记录中过滤掉其哪几组