MySQL查询每个部门的最高薪水

假设有两个表Department和Employee。

department的表结构如下：

+-------+-------------+------+-----+---------+----------------+

| Field | Type        | Null | Key | Default | Extra          |

+-------+-------------+------+-----+---------+----------------+

| Id    | int(11)     | NO   | PRI | NULL    | auto_increment |

| Name  | varchar(60) | YES  |     | NULL    |                |

+-------+-------------+------+-----+---------+----------------+

employee表结构如下：

+--------------+-------------+------+-----+---------+----------------+

| Field        | Type        | Null | Key | Default | Extra          |

+--------------+-------------+------+-----+---------+----------------+

| Id           | int(11)     | NO   | PRI | NULL    | auto_increment |

| Name         | varchar(60) | YES  |     | NULL    |                |

| Salary       | double(9,2) | YES  |     | NULL    |                |

| DepartmentId | int(11)     | YES  | MUL | NULL    |                |

+--------------+-------------+------+-----+---------+----------------+

现在要查询每个部门的最高薪水，查询语句如下：

SELECT
d. NAME Department,
e. NAME Employee,
e.Salary Salary
FROM
Employee e
JOIN (
SELECT
MAX(Salary) max,
DepartmentId
FROM
Employee
GROUP BY
DepartmentId
) g ON e.DepartmentId = g.DepartmentId
JOIN Department d ON (e.DepartmentId = d.Id)
WHERE
e.Salary = g.max;