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.maxsalFROM employee eINNER JOIN(SELECT e.departmentid,d.name,MAX(salary) maxsalFROM employee eINNER JOIN department don e.departmentid = d.idGROUP BY e.departmentid,d.name) ton e.departmentid = t.departmentidWHERE e.salary=t.maxsal
