SELECT his.emp_no,today.salary-his.salary FROM -- 求出所有员工最早入职工资 (SELECT emp_no,MIN(from_date),salary FROM salaries s GROUP by emp_no) his, -- 求出在职的员工当前工资 (SELECT emp_no,salary,s.to_date FROM salaries s WHERE s.to_date = '9999-01-01') today WHERE his.emp_no = today.emp_no ORDER BY today.salary-his.salary asc