关于SQL查询？

Question

  

可能重复：
  Employee Manager Report - Sql Server

我有一个Employee表，如下所示：

Eno Ename   Mangerid
1    X      Null
2    Y      1
3    Z      2

但我希望结果如下所示

Ename    Managername
X        Null
Y        X
Z        y

任何人都可以给我答案吗？

提前致谢

Answer 1

这应该有效：

select 
    e.Ename,
    m.Ename as ManagerName
from employee e
left join employee m on e.ManagerId = m.Eno

Answer 2

select e1.Ename employee, e2.Ename manager
from employee e1
join employee e2 on e1.ManagerId = e2.Eno

Answer 3

在员工表上使用自我加入

    SELECT EMPLOYEE.ENAME as EmployeeName, EMPLOYEE.ENO as ManagerName
 FROM EMPLOYEE 
INNER JOIN EMPLOYEE AS EMPLOYEE_1 
ON EMPLOYEE.ENO = EMPLOYEE_1.MANEGERID

---

Answer 4

您应该使用递归CTE

Recursive Queries Using Common Table Expressions

您可以根据需要深入了解层次结构。

Answer 5

Select e.Name, (select m.name from Employee M where M.Eno =e.Mangerid) as Manager
from Employee e