解题思路

1.查询调整后且在职的员工薪酬信息，作为新表t1

select emp_no,salary 
from salaries
where to_date='9999-01-01';

2.查询调整前的员工薪酬信息,并作为新表t2

select s.emp_no,s.salary
from salaries as s 
inner join employees as e
on s.emp_no = e.emp_no
and s.from_date =e.hire_date;

3.薪酬涨幅为t1.salary-t2.salary

select t1.emp_no, (t1.salary-t2.salary) as growth
from 
    (select emp_no,salary 
    from salaries
    where to_date='9999-01-01') as t1
inner join 
    (select s.emp_no,s.salary
    from salaries as s 
    inner join employees as e
    on s.emp_no = e.emp_no
    and s.from_date =e.hire_date) as t2
on t1.emp_no = t2.emp_no
order by growth asc;