题解 | #查找在职员工自入职以来的薪水涨幅情况#

select 
a.emp_no,g.salary - h.salary growth 
from employees a
left join
    (
    select   
    b.emp_no,b.salary
    from  employees  a
    left join  salaries b
        on  a.emp_no  = b.emp_no 
        and a.hire_date  = b.from_date 
    )h
    on  a.emp_no = h.emp_no
inner  join  
    (
    select   
    distinct  emp_no,salary
    from
    salaries
    where  to_date ='9999-01-01'
    )g
    on  h.emp_no  = g.emp_no 

order  by  (g.salary - h.salary )



分两部分
1.算出入职前的工资。
2.算出现在的工资。
再将两部分工资相减