问题
I have this table:
Name Null? Type
-------------------------- -------- ------------
EMPLOYEENO NOT NULL NUMBER(4)
ENAME VARCHAR2(15)
JOB VARCHAR2(15)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER
COMM NUMBER
DEPTNO NUMBER(2).
I want to get the department with minimum employees who have a given job (for example all the employees with 'Analyst' job).
Can you please help me with the query?
回答1:
Here the key is to get the count of Employee doing particular job in each department. In below query, this is achieved by subquery. Then, we want to get the Department with minimum no. of employee doing that job so we ordered the records returned by subquery in ascending and then select the first result by using rownum = 1
SELECT DEPTNO from (
SELECT COUNT(*) AS NO_OF_EMP , DEPTNO
FROM EMPLOYEE EMP
WHERE EMP.JOBNAME = 'Analyst'
GROUP BY DEPTNO
ORDER BY NO_OF_EMP ASC )
where ROWNUM = 1;
回答2:
Given that the minimum number of such employees could be 0, you need to be a bit clever about how you do this:
select d.*
from (select deptno,
sum(case when jobname = 'Analyst' then 1 else 0 end) as numAnalysts
from employees
group by deptno
order by numAnalysts asc
) d
where rownum = 1;
来源：https://stackoverflow.com/questions/29316840/get-the-minimum-employees-with-a-given-job