SQL> select n1,v1,nid,sum(nid) over(order by nid) as sum
2 from t1;
N1 V1 NID SUM
---------- ---------- ---------- ----------
1 aa 61 61
2 aa 62 123
3 aa 63 186
4 aa 64 250
取nid列的累积和，即下面以emp表为例的按部门“连续”求总和
==================================================================
按v1分组取nid的和
SQL> select v1,sum(nid) over (partition by v1 order by v1) as sum_nid from t1;
V1 SUM_NID
---------- ----------
aa 187
aa 187
aa 187
bb 83
按v1分组取nid的和，并重复行只显示一行
SQL> select distinct * from (select v1,sum(nid) over (partition by v1) as sum_nid from t1);
V1 SUM_NID
---------- ----------
aa 187
bb 83
==================================================================
再以emp为例
使用子分区查出各部门薪水连续的总和。注意按部门分区 over(...)条件的不同
sum(sal) over (partition by deptno order by ename) 按部门“连续”求总和
sum(sal) over (partition by deptno) 按部门求总和
sum(sal) over (order by deptno，ename) 不按部门“连续”求总和
sum(sal) over () 不按部门，求所有员工总和，效果等同于sum(sal)。
sql> break on deptno skip 1 -- 为效果更明显，把不同部门的数据隔段显示。
SQL> select deptno,ename,sal,
2 sum(sal) over (partition by deptno order by ename) 部门连续求和,
3 sum(sal) over (partition by deptno) 部门总和,
4 100*round(sal/sum(sal) over (partition by deptno),4) 部门份额,
5 sum(sal) over () 总和,
6 sum(sal) over (order by deptno,ename) 连续求和,
7 100*round(sal/sum(sal) over (),4) 总份额
8 from emp;
DEPTNO ENAME SAL 部门连续求和 部门总和 部门份额 总和 连续求和 总份额
---------- ---------- ---------- ------------ ---------- ---------- ---------- ---------- ----------
10 CLARK 2450 2450 8750 28 29025 2450 8.44
KING 5000 7450 8750 57.14 29025 7450 17.23
MILLER 1300 8750 8750 14.86 29025 8750 4.48
20 ADAMS 1100 1100 10875 10.11 29025 9850 3.79
FORD 3000 4100 10875 27.59 29025 12850 10.34
JONES 2975 7075 10875 27.36 29025 15825 10.25
SCOTT 3000 10075 10875 27.59 29025 18825 10.34
SMITH 800 10875 10875 7.36 29025 19625 2.76
30 ALLEN 1600 1600 9400 17.02 29025 21225 5.51
BLAKE 2850 4450 9400 30.32 29025 24075 9.82
JAMES 950 5400 9400 10.11 29025 25025 3.27
MARTIN 1250 6650 9400 13.3 29025 26275 4.31
TURNER 1500 8150 9400 15.96 29025 27775 5.17
WARD 1250 9400 9400 13.3 29025 29025 4.31
已选择14行。
综合的例子，求和规则有按部门分区的，有不分区的例子
SQL> select deptno,ename,sum(sal) over(partition by deptno order by sal) as sum_sal,
2 sum(sal) over(order by deptno,sal) as sum_dept_sal
3 from emp;
DEPTNO ENAME SUM_SAL SUM_DEPT_SAL
---------- ---------- ---------- ------------
10 MILLER 1300 1300
CLARK 3750 3750
KING 8750 8750
20 SMITH 800 9550
ADAMS 1900 10650
JONES 4875 13625
SCOTT 10875 19625
FORD 10875 19625
30 JAMES 950 20575
WARD 3450 23075
MARTIN 3450 23075
TURNER 4950 24575
ALLEN 6550 26175
BLAKE 9400 29025
已选择14行。
来一个逆序的，即部门从大到小排列，部门里各员工的薪水从高到低排列，累计和的规则不变。
SQL> select deptno,ename,sal,
2 sum(sal) over (partition by deptno order by deptno desc,sal desc) as sum_sal_order,
3 sum(sal) over (order by deptno desc,sal desc) as sum
4 from emp;
DEPTNO ENAME SAL SUM_SAL_ORDER SUM
---------- ---------- ---------- ------------- ----------
30 BLAKE 2850 2850 2850
ALLEN 1600 4450 4450
TURNER 1500 5950 5950
WARD 1250 8450 8450
MARTIN 1250 8450 8450
JAMES 950 9400 9400
20 SCOTT 3000 6000 15400
FORD 3000 6000 15400
JONES 2975 8975 18375
ADAMS 1100 10075 19475
SMITH 800 10875 20275
10 KING 5000 5000 25275
CLARK 2450 7450 27725
MILLER 1300 8750 29025
已选择14行。