方法一: 两表联查 然后再连接新水表
select t1.emp_no, t3.salary - t2.salary as growth
from employees t1 join salaries t2
on t1.emp_no = t2.emp_no and t1.hire_date = t2.from_date
join salaries t3
on t1.emp_no = t3.emp_no and t3.to_date = '9999-01-01'
order by growth;
方法二: 两表联查 条件 必须有一个表 to_date = '9999-01-01' 目的是为了获取到最高工资 以 emp_no 分组后 直接找出 salary 最小值 最高工资减最低工资即为涨幅情况
select t1.emp_no, (t2.salary - min(t1.salary)) growth
from salaries as t1, salaries as t2
where t1.emp_no = t2.emp_no and t2.to_date = '9999-01-01'
group by t1.emp_no
order by growth;