MYSQL 寒假自学 2022 十二 （十一）

-- 头尾函数,到当前行，为止
select 
 dname,
 ename,
 salary,
 hiredate,
 first_value(salary) over(partition by dname order by hiredate)as first,
 last_value(salary) over(partition by dname order by hiredate )as last
from employee;