找出每个组的最大值以及名称

Question

我有一个表Employee，其内容如下

-------------------------------------------------------------------
Name                       Department                  Salary
-------------------------------------------------------------------
Hemant                      PTS                         100
Gunjan                      PTS                         101
Amol                        ADM                         50
Parthiv                     ADM                         60
-------------------------------------------------------------------

我想写一个SINGLE查询来显示PTS最高工资消费者群体的名称。 换句话说，查询的输出应该是Gunjan和Parthiv来自不同的部门并且在该部门获得最高薪水。

-------------------------------------------------------------------
Name                       Department                  Salary
-------------------------------------------------------------------
Gunjan                      PTS                         101
Parthiv                     ADM                         60
-------------------------------------------------------------------

以下查询工作正常

SELECT E.Department,MAX(E.Salary) FROM 
Employee E
GROUP BY Department;

但是如何选择名称以及部门和Max（薪资）？

Answer 1

由于你没有提到任何RDBMS，下面的这个查询几乎可以在任何RDBMS上工作（但不是我猜的全部）

SELECT  a.*
FROM    Employee a
        INNER JOIN
        (
            SELECT  Department, MAX(Salary) Max_Val
            FROM    Employee
            GROUP   BY Department
        ) b ON a.Department = b.Department AND
                a.Salary = b.Max_Val

• SQLFiddle Demo

输出

╔═════════╦════════════╦════════╗
║  NAME   ║ DEPARTMENT ║ SALARY ║
╠═════════╬════════════╬════════╣
║ Gunjan  ║ PTS        ║    101 ║
║ Parthiv ║ ADM        ║     60 ║
╚═════════╩════════════╩════════╝