Question

执行查询时出错。我不知道这似乎是什么问题。我正在尝试查询数据库，以找出两个或更多部门的员工。（即Staff_ID = 1，在DEPT_ID = 4和6下工作）。涉及三个表：

1. STAFF
2. DEPARTMENT
3. STAFF_DEPT (contains ID of STAFF and DEPT)

这就是我所做的，

SELECT
sd.STAFF_ID || ' ' || s.STAFF_NAME AS "Staff Name",
d.DEPT_NAME AS "Department"
FROM STAFF_DEPT sd
INNER JOIN STAFF s ON sd.STAFF_ID = s.STAFF_ID 
INNER JOIN DEPARTMENT d ON sd.DEPT_ID = d.DEPT_ID
GROUP BY sd.STAFF_ID
HAVING COUNT (sd.STAFF_ID) > 1

Answer 1

这是您的原始查询：

SELECT sd.STAFF_ID || ' ' || s.STAFF_NAME AS "Staff Name",
       d.DEPT_NAME AS "Department"
FROM STAFF_DEPT sd
INNER JOIN STAFF s ON sd.STAFF_ID = s.STAFF_ID 
INNER JOIN DEPARTMENT d ON sd.DEPT_ID = d.DEPT_ID
GROUP BY sd.STAFF_ID
HAVING COUNT (sd.STAFF_ID) > 1;

您的查询存在的问题是您正在对staff_id进行汇总，但您的汇总中有staff_name和dept_name列。您正在寻找多个部门的员工。您可以使用以下命令获得每人一行的部门列表：

SELECT sd.STAFF_ID || ' ' || s.STAFF_NAME AS "Staff Name",
       list_agg(d.DEPT_NAME, ',') within group (order by DEPT_NAME) AS "Department_List"
FROM STAFF_DEPT sd
INNER JOIN STAFF s ON sd.STAFF_ID = s.STAFF_ID 
INNER JOIN DEPARTMENT d ON sd.DEPT_ID = d.DEPT_ID
GROUP BY sd.STAFF_ID, s.STAFF_Name
HAVING COUNT (sd.STAFF_ID) > 1;

注意：我在list_agg()和select s.staff_name中添加了group by。

如果您想要每行一个人/部门，那么请使用带有分析函数的子查询：

selectsd.STAFF_ID || ' ' || s.STAFF_NAME AS "Staff Name", dept_name
from (select sd.staff_id, s.staff_name, d.dept_name,
             count(*) over (partition by sd.staff_id, s.staff_name) as NumDepts
      FROM STAFF_DEPT sd
      INNER JOIN STAFF s ON sd.STAFF_ID = s.STAFF_ID 
      INNER JOIN DEPARTMENT d ON sd.DEPT_ID = d.DEPT_ID
     ) t
where NumDepts > 1;

Answer 2

试试这个：

with temp as
(select sd.staff_id from staff_dept sd
group by staff_id
having count(staff_id)>1)
select tp.staff_id||' ' ||s.Name AS "Staff Name", d.DNAME
FROM temp tp, 
staff_dept sd,
staff s,
dept d
where tp.staff_id=sd.staff_id
and sd.staff_id=s.id
and sd.dept_id=d.deptno;

我在临时视图中存储了employee_id的计数超过1，并在最终的选择查询中使用它。

正如我之前向techdo提到的那样，你不能通过sd.STAFF_ID ||进行分组''|| s.STAFF_NAME，d.DEPT_NAME，因为它始终是唯一的，并且总是算作1。

Answer 3

请尝试：

SELECT
  sd.STAFF_ID || ' ' || s.STAFF_NAME AS "Staff Name",
  d.DEPT_NAME AS "Department"
FROM STAFF_DEPT sd
  INNER JOIN STAFF s ON sd.STAFF_ID = s.STAFF_ID 
  INNER JOIN DEPARTMENT d ON sd.DEPT_ID = d.DEPT_ID
GROUP BY sd.STAFF_ID || ' ' || s.STAFF_NAME, d.DEPT_NAME
HAVING COUNT (sd.STAFF_ID) > 1

查询来自两个或更多部门的员工

3 个答案: