Mysql 选择每个工资高于其部门平均工资的员工

我的数据库中只有一个名为EMPLOYEE的表，其中有3个表：

Employee_Name, Employee_Salary, Department_ID

现在，我必须选择每一位工资高于其部门平均水平的员工我该怎么做？

我面临的主要问题是，在比较每个员工的工资时

SELECT  AVG(department_ID) FROM employee GROUP BY Department_ID

内部队列的返回集返回多行

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我想我需要执行联接操作，但我不知道如何执行。

试试这个。。。这一点没有经过测试

SELECT * from employee join (SELECT AVG(employee_salary) as sal, department_ID 
FROM employee GROUP BY Department_ID) as t1 
ON employee.department_ID = t1.department_ID 
where employee.employee_salary > t1.sal

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请尝试以下查询

Select * from employee a where Employee_Salary > (select avg(Employee_Salary) from 
employee b group by Department_ID having b.Department_ID = a.Department_ID)

或

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在不分组的情况下尝试此项

SELECT * FROM employee  E1 
WHERE [Employee_Salary] > (
                            SELECT AVG([Employee_Salary]) FROM employee  E2 
                            WHERE E2.[Department_ID] = E1.[Department_ID]
                           )

尝试使用

EXISTS（）

如：

SELECT t1.Employee_Name, t1.Employee_Salary, t1.Department_ID
FROM Employee t1
WHERE EXISTS
(
 SELECT t2.Department_ID, AVG(t2.Employee_Salary) as AvgSalary
 FROM Employee t2
 WHERE   t1.Department_ID = t2.Department_ID
 GROUP BY t2.Department_ID
 HAVING t1.Employee_Salary>AVG(t2.Employee_Salary)

))

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请参见

您也可以尝试这种方法

  select FirstName,E.DepartmentName,BaseRate,EB.avgSAL
  From DimEmployee E
  inner join
  (select avg(BaseRate) As avgSAL,DepartmentName
  from DimEmployee
  group by DepartmentName ) EB
  ON E.DepartmentName = Eb.DepartmentName
  where E.BaseRate > Eb.avgSAL

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担任博士后，

试试这个

select e1.* from emp e1  inner join (select avg(sal) avg_sal,dept_id from emp group by dept_id) as e2 on e1.dept_id=e2.dept_id and e1.sal>e2.avg_sal

也可以尝试以下方法：

Select e.ename, e.sal, e.deptno
from (select e.*, avg(sal) over (partition by deptno) as avgsalary
      from EMP_TABLE e
     ) e
where e.sal > e.avgsalary;

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第一个问题解决了，非常感谢。请详细说明一下HAVING命令的用法好吗？这是我唯一没有真正理解的部分。两个查询都可以。Having通常用于过滤分组结果。并且它仅与GROUPBY子句一起使用。”where'子句通常用于过滤结果并执行操作。这将首先过滤出结果，然后在deptid上应用groupby。希望这个解释对你有用。@tκηηπαλσαμδηη你确定吗？

Select e.ename, e.sal, e.deptno
from (select e.*, avg(sal) over (partition by deptno) as avgsalary
      from EMP_TABLE e
     ) e
where e.sal > e.avgsalary;