oracle累积求和分析函数sum over的使用

示例1:
select deptno,ename,job,sal,sum(sal) over(order by sal) he from emp;

结果：
20	SMITH	CLERK	  800	800
30	JAMES	CLERK	  950	1750
20	ADAMS	CLERK	  1100	2850
30	WARD	SALESMAN  1250	5350
30	MARTIN	SALESMAN  1250	5350
10	MILLER	CLERK	  1300	6650
30	TURNER	SALESMAN  1500	8150
30	ALLEN	SALESMAN  1600	9750

示例2:
select deptno,ename,sal,sum(sal) over(partition by deptno order by ename) he from emp;
结果:
10	CLARK	2450	2450
10	KING	5000	7450
10	MILLER	1300	8750
20	ADAMS	1100	1100
20	FORD	3000	4100
20	JONES	2975	7075
20	SCOTT	3000	10075
20	SMITH	800	10875
30	ALLEN	1600	1600
30	BLAKE	2850	4450