SELECT s1.emp_no,s2.salary - s1.salary growth
FROM 
(SELECT salaries.emp_no,salary FROM salaries ,employees
 WHERE salaries.from_date = employees.hire_date AND salaries.emp_no = employees.emp_no) s1 ,
(SELECT salaries.emp_no,salary FROM salaries,employees 
 WHERE salaries.to_date = '9999-01-01'AND salaries.emp_no = employees.emp_no) s2
WHERE s1.emp_no = s2.emp_no
ORDER BY growth ASC

创建两张子表 s1 s2
s1 是员工初始工资表
s2 是员工当前工资表
s2.salary - s1.salary 就是 薪水的涨幅情况