MySQL_项目7: 各部门工资最高的员工（难度：中等）

项目七: 各部门工资最高的员工（难度：中等）

创建Employee 表，包含所有员工信息，每个员工有其对应的 Id, salary 和 department Id。

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

| Id | Name | Salary | DepartmentId |

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

| 1 | Joe | 70000 | 1 |

| 2 | Henry | 80000 | 2 |

| 3 | Sam | 60000 | 2 |

| 4 | Max | 90000 | 1 |

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

-- 创建employee表
CREATE TABLE employee (
id int(11) NOT NULL,
name varchar(50) NOT NULL,
salary decimal(10,2) NOT NULL DEFAULT '0.00',
departmentid int(11) NOT NULL,
PRIMARY KEY (`id`));

-- 插入数据
INSERT INTO `employee` VALUES ('1', 'Joe', '70000.00', '1');
INSERT INTO `employee` VALUES ('2', 'Herry', '80000.00', '2');
INSERT INTO `employee` VALUES ('3', 'Sam', '60000.00', '2');
INSERT INTO `employee` VALUES ('4', 'Max', '90000.00', '1');
INSERT INTO `employee` VALUES ('5', 'Janet', '69000.00', '1');
INSERT INTO `employee` VALUES ('6', 'Randy', '85000.00', '1');
INSERT INTO `employee` VALUES ('7', 'sherry', '90000.00', '1');
INSERT INTO `employee` VALUES ('8', 'haha', '80000.00', '2');
INSERT INTO `employee` VALUES ('9', 'Abbo', '80800.00', '3');

创建Department 表，包含公司所有部门的信息。

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

| Id | Name |

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

| 1 | IT |

| 2 | Sales |

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

-- 创建department表
CREATE TABLE department (
id int(11) NOT NULL,
name varchar(100) NOT NULL,
PRIMARY KEY (`id`));

-- 插入数据
INSERT INTO `department` VALUES ('1', 'IT');
INSERT INTO `department` VALUES ('2', 'Sales');
INSERT INTO `department` VALUES ('3', 'customs');

编写一个 SQL 查询，找出每个部门工资最高的员工。例如，根据上述给定的表格，Max 在 IT 部门有最高工资，Henry 在 Sales 部门有最高工资。

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

| Department | Employee | Salary |

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

| IT | Max | 90000 |

| Sales | Henry | 80000 |

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

 

注意点：需要考虑同部门最高工资有多个人的情况

SELECT e.*,t.name department,t.maxsal
FROM employee e
INNER JOIN
                    (SELECT e.departmentid,d.name,MAX(salary) maxsal
                    FROM employee e
                    INNER JOIN department d
                    on e.departmentid = d.id
                    GROUP BY e.departmentid,d.name) t
on e.departmentid = t.departmentid

WHERE e.salary=t.maxsal