以下SQL查询的正确解决方案是什么？

Question

Print name of all activities with neither maximum nor minimum number of participants

我已经尝试过以下查询，但给我错误：

select ACTIVITY
from (select ACTIVITY, count(*) as cnt,
             max(count(*)) as max_cnt,
             min(count(*)) as min_cnt
      from FRIENDS GROUP BY ACTIVITY) FRIENDS
where cnt not in (max_cnt, min_cnt);

错误：第1行的错误1111（HY000）：无效使用组功能MYSQL版本：8

Answer 1

大概，您没有运行MySQL 8.0（否则，您上一个问题给出的答案将是可行的。）>

在较早的版本中，您可以这样做：

select activity, count(*) no_activities
from friends
group by activity
having 
        count(*) > (select count(*) from friends group by activity order by count(*)  asc limit 1)
    and count(*) < (select count(*) from friends group by activity order by count(*) desc limit 1)

Answer 2

尝试以下操作，它应该使用MySQL 8.0中的窗口功能。

Answer 3

您想要窗口功能：