select r.emp_no,(b.s2-r.s1) as growth from(select salaries.emp_no ,salary s1 from salaries join employees on salaries.emp_no = employees.emp_no where salaries.from_date = employees.hire_date)r join( select salaries.emp_no ,salary s2 from salaries join employees on salaries.emp_no = employees.emp_no where to_date ='9999-01-01' ) b on r.emp_no = b.emp_no order by growth asc

思路

首先对表salaries和表employees使用内连接，连接条件是 salaries.emp_no = employees.emp_no，查询出员工的员工号和入职薪水记为r，同理查询出在职员工的员工号和目前薪水记为b，最后将这两个中间表使用内连接,连接条件是emp_no相等，最后查询出该表的emp_no和（b.salary-r.salary）,按照薪水涨幅生序排列即可。