如何在SQL查询中显示employee表中的经理姓名？

我有一个employee表，显示员工编号、姓名和经理的员工编号。我正在尝试创建一个显示emp名称、emp、经理名称和经理的查询

该表如下所示：

EMPNO ENAME  JOB       MGR  HIREDATE  SAL COMM DEPTNO 
7839  KING   PRESIDENT -    17-NOV-81 5000 -   10 
7698  BLAKE  MANAGER   7839 01-MAY-81 2850 -   30 
7782  CLARK  MANAGER   7839 09-JUN-81 2450 -   10 
7566  JONES  MANAGER   7839 02-APR-81 2975 -   20 
7654  MARTIN SALESMAN  7698 28-SEP-81 1250 1400 30 
7499  ALLEN  SALESMAN  7698 20-FEB-81 1600 300 30 
7844  TURNER SALESMAN  7698 08-SEP-81 1500 0   30 
7900  JAMES  CLERK     7698 03-DEC-81 950  -   30 
7521  WARD   SALESMAN  7698 22-FEB-81 1250 500 30 
7902  FORD   ANALYST   7566 03-DEC-81 3000 -   20 

其中三列非常简单，因为它们在表中，但是当我只有经理的员工编号时，如何添加经理姓名

这是我到目前为止只显示了3列的内容

select ename as "Employee", empno as "Emp#", mgr as "Mgr#"  from emp;

任何帮助都将不胜感激

请尝试以下方法：

select 
  emp.ename as "Employee", 
  emp.empno as "Emp#", 
  emp.mgr as "Mgr#",
  m.ename as "Manager"
from 
 emp
  LEFT OUTER JOIN emp m ON
   emp.mgr = m.empno

select e.ename ,e.sal, (select s.grade from salgrade s where e.sal between s.losal and s.hisal) empgrade ,e2.ename"mgr", e2.sal mgrsal,
(select s.grade from salgrade s where e2.sal between s.losal and s.hisal) mgrgrade from emp e,emp e2
where e.mgr=e2.empno(+)

试试这个：

select e.ename ,e.sal, (select s.grade from salgrade s where e.sal between s.losal and s.hisal) empgrade ,e2.ename"mgr", e2.sal mgrsal,
(select s.grade from salgrade s where e2.sal between s.losal and s.hisal) mgrgrade from emp e,emp e2
where e.mgr=e2.empno(+)

这将为您提供不同的员工姓名，他们是经理

或：

或：

这将为您提供不同的员工姓名，他们是经理

或：

或：

---

我试过了，效果很好

SELECT a.empno EmpID,a.empname EmpName, a.mgrid MgrID,(select empname from employee where empno = a.mgrid) MgrName 
from employee a, employee b
where a.empno = b.empno order by a.empno asc;

---

我试过了，效果很好

SELECT a.empno EmpID,a.empname EmpName, a.mgrid MgrID,(select empname from employee where empno = a.mgrid) MgrName 
from employee a, employee b
where a.empno = b.empno order by a.empno asc;

请尝试此查询

SELECT E2.EMPID,E2.EMPNAME,E1.EMPNAME 
AS MGRNAME 
FROM employee E1 
   INNER JOIN employee E2 ON E1.Empid=E2.ManagerId

请尝试此查询

SELECT E2.EMPID,E2.EMPNAME,E1.EMPNAME 
AS MGRNAME 
FROM employee E1 
   INNER JOIN employee E2 ON E1.Empid=E2.ManagerId

---

通常，对于计算工作，我们只需要数据——不修饰。UI和装饰应该留给一个单独的层，而不应该处理或装饰空值！在做所有这些事情的同时，你的答案也漏掉了所有其他（有用的）专栏。通常对于计算工作，我们只需要数据——不修饰。UI和装饰应该留给一个单独的层，而不应该处理或装饰空值！在做所有这些事情的同时，你的答案也漏掉了所有其他（有用的）专栏。

select   e.ename as "Employee",  e.empno as "Emp#",  e.mgr as "Mgr#",  m.ename as "MgrName" from emp e ,  emp m   on e.mgr = m.empno

SELECT a.empno EmpID,a.empname EmpName, a.mgrid MgrID,(select empname from employee where empno = a.mgrid) MgrName 
from employee a, employee b
where a.empno = b.empno order by a.empno asc;

SELECT E2.EMPID,E2.EMPNAME,E1.EMPNAME 
AS MGRNAME 
FROM employee E1 
   INNER JOIN employee E2 ON E1.Empid=E2.ManagerId

Select e.ename empname , m.ename managername,e.empno empno ,m.mgr managerno from emp e, mgr m
where m.empno=e.mgr