题解 | #查找在职员工自入职以来的薪水涨幅情况#

select salaries.emp_no, salaries.salary - min_salary as growth
from salaries
join 
(select emp_no, max(from_date) as max_time, min(salary) as min_salary
from salaries
where emp_no in (select emp_no
from salaries
where to_date = "9999-01-01")
group by emp_no) t
on salaries.emp_no = t.emp_no
where salaries.from_date = t.max_time
order by growth asc

首先先筛选出在职员工的编号、在职员工最近一次发工资的时间（max(from_date)），和职工最低工资（一般是刚入职，min(salary)）（t）

然后根据将t与salaries进行连接，并且筛选出最近一次发工资的记录（salaries.from_date = t.max_time），此时可以查询出每个员工的员工的编号、当前工资、最低工资（min_salary，子查询中的）等数据，select选择出相应的字段进行相减即可，最后再使用order by对涨幅进行升序排序即可