Question

假设我们有以下表格：

company             company_has_employee        employee
-------------------------------------------------------------
id                  company_id                  id  
companzy_name       employee_id                 emplyee_name

如何创建SQL Query，它检索任何两名员工，谁为同一家公司工作，该公司是什么？

Answer 1

select company_name, 
       min(e.employee_name) as emp1, 
       max(e.employee_name) as emp2
from compyny c
join company_has_employee ce on ce.company_id = c.id
join employee e on e.id = cs.employee_id
group by company_name
having count(e.id) > 1

Answer 2

假设juergen d表的连接是正确的，我会将查询修改为

select top 2 company_name, e.employee_name
   from compyny c
   join company_has_employee ce on ce.company_id = c.id
   join employee e on e.id = cs.employee_id
   group by company_name
   having count(e.id) > 1

这将始终返回前2名员工

juergen d的原始查询将始终根据其ID返回第一个和最后一个员工。

如果你想随机选择两名员工，那么你可以试试这个：

select top 2 company_name, e.employee_name
   from compyny c
   join company_has_employee ce on ce.company_id = c.id
   join employee e on e.id = cs.employee_id
   group by company_name
   having count(e.id) > 1
   order by RAND((e.ID)*DATEPART(millisecond, GETDATE()))

最后一个order by子句将随机更改记录的顺序，您将始终获得随机顺序的前2位...这意味着每次运行查询时都会选择2名随机员工。

查询选择：两名员工是谁为同一家公司工作

2 个答案: