瞎写的思路还过了，把薪水依次上移动一位，然后结束日期找到2024-01-01,用日薪-之前的日薪就哦了
with tiaojian as (
select 
雇员编号,
薪水,
lead(薪水,1)over(partition by 雇员编号 order by 薪水 desc) as pn
,结束日期
from 薪水表
)


select 
雇员编号,
ifnull(
sum(薪水)-sum(pn),0) as 薪水涨幅
from tiaojian 
where
结束日期="2004-01-01"
group by 雇员编号