本文介绍了解决查询所需的帮助的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
1254 TANS MANAGER 5555 09-OCT-91 5000 5500 30
123 VIDYA
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
在此表中我想
显示所有仅为一名员工担任经理的员工。
我尝试了什么:
in this table i wants to
Display all the employees who is working as manager for only one employee.
What I have tried:
select *from emp where empno in (select mgr from emp where job = 'MANAGER')
i厌倦了这个SQL查询,但我不是确定天气是否正确。请帮我纠正。
i tired this sql query but i am not sure weather it is correct or not. please help me to correct.
推荐答案
SELECT Mgr, COUNT(mgr) As [Count] FROM emp
GROUP BY Mgr
HAVING COUNT(Mgr) = 1
然后您可以使用JOIN获取经理详细信息:
You can then use JOIN to get the manager details:
SELECT * FROM emp e
JOIN (SELECT mgr, COUNT(mgr) As [Count] FROM emp
GROUP BY Mgr
HAVING COUNT(Mgr) = 1) c
ON e.EmpNo = c.Mgr
这篇关于解决查询所需的帮助的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!