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 ; 分组后注意使用having进行过滤,注意分组函数是不可以使用where的,分为where语句执行的顺序在分组函数的前面