21、查找所有员工自入职以来的薪水涨幅情况

查找所有员工自入职以来的薪水涨幅情况，给出员工编号emp_no以及其对应的薪水涨幅growth，并按照growth进行升序
CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_no`));
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));

无

select ns.emp_no,(ns.salary-hs.salary) as growth
from
(select e.emp_no,s.salary 
from employees e left join salaries s on e.emp_no=s.emp_no
where s.to_date=‘9999-01-01‘) as ns
join 
(select e.emp_no,s.salary 
from employees e left join salaries s on e.emp_no=s.emp_no
where s.from_date=e.hire_date) as hs
on ns.emp_no=hs.emp_no
order by growth;