题解 | #统计salary的累计和running_total#

SELECT emp_no,
       salary,
       sum(salary) over (order by emp_no) running_total
FROM salaries
where to_date='9999-01-01'
;

1. 窗口函数，这里不需要分组，就不用partition by
2. order by的默认就是第一行到当前行，所以不需要特意指出

   rows between unbounded preceding 
        and  current row
   

```