从嵌套查询中获取拖动列

Question

使用以下代码我得到最大值

select
  max(e.maxNum)
from (select
    companyno as cn,
    count(employeeNo) as maxNum
      from works
      group by companyNo) e;

但我也需要像“companyno，e.maxNum”这样的“companyNo”

我试过

select
  e.cn,
  max(e.maxNum)
from (select
    companyno as cn,
    count(employeeNo) as maxNum
      from works
      group by companyNo) e;

但我收到错误

如何解决这个问题？

表格式

works(employeeNo, companyNo, salary)
company(companyNo, companyName, city)

Answer 1

select 
  max(CompanyNo) keep (dense_rank first order by count(employeeNo) desc) as cn,
  max(count(employeeNo)) maxNum
from Works
group by CompanyNo

fiddle