Oracle中over函数的使用示例
转自?http://www.cnblogs.com/umen/archive/2011/04/11/2012136.html
?
?
Oracle over函数
SQL code:?
WITH
OBJ AS(
SELECT
name, type
?
目的：以oracle自带的scott模式为测试环境，主要通过试验体会分析函数的用法。
类似 sum(...) over ... 的使用
1.原表信息：
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 from emp
3 order by deptno;
??? DEPTNO ENAME???????????? SAL
---------- ---------- ----------
??????? 10 CLARK??????????? 2450
?????????? KING???????????? 5000
?????????? MILLER?????????? 1300
??????? 20 SMITH???????????? 800
?????????? ADAMS??????????? 1100
?????????? FORD???????????? 3000
?????????? SCOTT??????????? 3000
?????????? JONES??????????? 2975
??????? 30 ALLEN??????????? 1600
?????????? BLAKE??????????? 2850
?????????? MARTIN?????????? 1250
?????????? JAMES???????????? 950
?????????? TURNER?????????? 1500
?????????? WARD???????????? 1250
已选择14行。
2.先来一个简单的，注意over(...)条件的不同，
使用 sum(sal) over (order by ename)... 查询员工的薪水“连续”求和,
注意over (order by ename)如果没有order by 子句，求和就不是“连续”的，
放在一起，体会一下不同之处：
SQL> break on '' -- 取消数据分段显示
SQL> select deptno,ename,sal,
2 sum(sal) over (order by ename) 连续求和,
3 sum(sal) over () 总和,????????????????? -- 此处sum(sal) over () 等同于sum(sal)
4 100*round(sal/sum(sal) over (),4) "份额(%)"
5 from emp
6 /
??? DEPTNO ENAME???????????? SAL?? 连续求和?????? 总和??? 份额(%)
---------- ---------- ---------- ---------- ---------- ----------
??????? 20 ADAMS??????????? 1100?????? 1100????? 29025?????? 3.79
??????? 30 ALLEN??????????? 1600?????? 2700????? 29025?????? 5.51
??????? 30 BLAKE??????????? 2850?????? 5550????? 29025?????? 9.82
??????? 10 CLARK??????????? 2450?????? 8000????? 29025?????? 8.44
??????? 20 FORD???????????? 3000????? 11000????? 29025????? 10.34
??????? 30 JAMES???????????? 950????? 11950????? 29025?????? 3.27
??????? 20 JONES??????????? 2975????? 14925????? 29025????? 10.25
??????? 10 KING???????????? 5000????? 19925????? 29025????? 17.23
??????? 30 MARTIN?????????? 1250????? 21175????? 29025?????? 4.31
??????? 10 MILLER?????????? 1300????? 22475????? 29025?????? 4.48
??????? 20 SCOTT??????????? 3000????? 25475????? 29025????? 10.34
??????? 20 SMITH???????????? 800????? 26275????? 29025?????? 2.76
??????? 30 TURNER?????????? 1500????? 27775????? 29025?????? 5.17
??????? 30 WARD???????????? 1250????? 29025????? 29025?????? 4.31
已选择14行。
3.使用子分区查出各部门薪水连续的总和。注意按部门分区。注意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,--各部门的薪水"连续"求和
3 sum(sal) over (partition by deptno) 部门总和, -- 部门统计的总和，同一部门总和不变
4 100*round(sal/sum(sal) over (partition by deptno),4) "部门份额(%)",
5 sum(sal) over (order by deptno,ename) 连续求和, --所有部门的薪水"连续"求和
6 sum(sal) over () 总和, -- 此处sum(sal) over () 等同于sum(sal)，所有员工的薪水总和
7 100*round(sal/sum(sal) over (),4) "总份额(%)"
8 from emp
9 /
DEPTNO ENAME??? SAL 部门连续求和?? 部门总和 部门份额(%)?? 连续求和?? 总和 总份额(%)
------ ------ ----- ------------ ---------- ----------- ---------- ------ ----------
??? 10 CLARK?? 2450???????? 2450?????? 8750????????? 28?????? 2450 29025?????? 8.44
?????? KING??? 5000???????? 7450?????? 8750?????? 57.14?????? 7450 29025????? 17.23
?????? MILLER 1300???????? 8750?????? 8750?????? 14.86?????? 8750 29025?????? 4.48
??? 20 ADAMS?? 1100???????? 1100???? 10875?????? 10.11?????? 9850 29025?????? 3.79
?????? FORD??? 3000???????? 4100????? 10875?????? 27.59????? 12850 29025????? 10.34
?????? JONES?? 2975???????? 7075????? 10875?????? 27.36????? 15825 29025????? 10.25
?????? SCOTT?? 3000??????? 10075????? 10875?????? 27.59????? 18825 29025????? 10.34
?????? SMITH??? 800??????? 10875????? 10875??????? 7.36????? 19625 29025?????? 2.76
??? 30 ALLEN?? 1600???????? 1600?????? 9400?????? 17.02????? 21225 29025?????? 5.51
?????? BLAKE?? 2850???????? 4450?????? 9400?????? 30.32????? 24075 29025?????? 9.82
?????? JAMES??? 950???????? 5400?????? 9400?????? 10.11????? 25025 29025?????? 3.27
?????? MARTIN 1250???????? 6650?????? 9400??????? 13.3????? 26275 29025?????? 4.31
?????? TURNER 1500???????? 8150?????? 9400?????? 15.96????? 27775 29025?????? 5.17
?????? WARD??? 1250???????? 9400?????? 9400??????? 13.3????? 29025 29025?????? 4.31
已选择14行。
4.来一个综合的例子，求和规则有按部门分区的，有不分区的例子
SQL> select deptno,ename,sal,sum(sal) over (partition by deptno order by sal) dept_sum,
2 sum(sal) over (order by deptno,sal) sum
3 from emp;
??? DEPTNO ENAME???????????? SAL?? DEPT_SUM??????? SUM
---------- ---------- ---------- ---------- ----------
??????? 10 MILLER?????????? 1300?????? 1300?????? 1300
?????????? CLARK??????????? 2450?????? 3750?????? 3750
?????????? KING???????????? 5000?????? 8750?????? 8750
??????? 20 SMITH???????????? 800??????? 800?????? 9550
?????????? ADAMS??????????? 1100?????? 1900????? 10650
?????????? JONES??????????? 2975?????? 4875????? 13625
?????????? SCOTT??????????? 3000????? 10875????? 19625
?????????? FORD???????????? 3000????? 10875????? 19625
??????? 30 JAMES???????????? 950??????? 950????? 20575
?????????? WARD???????????? 1250?????? 3450????? 23075
?????????? MARTIN?????????? 1250?????? 3450????? 23075
?????????? TURNER?????????? 1500?????? 4950????? 24575
?????????? ALLEN??????????? 1600?????? 6550????? 26175
?????????? BLAKE??????????? 2850?????? 9400????? 29025
已选择14行。
5.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) dept_sum,
3 sum(sal) over (order by deptno desc,sal desc) sum
4 from emp;
??? DEPTNO ENAME???????????? SAL?? DEPT_SUM??????? 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
?? ??? MITH???????????? 800????? 10875????? 20275
??????? 10 KING???????????? 5000?????? 5000????? 25275
?????????? CLARK??????????? 2450?????? 7450????? 27725
?????????? MILLER?????????? 1300?????? 8750????? 29025
已选择14行。
6.体会：在"... from emp;"后面不要加order by 子句，使用的分析函数的(partition by deptno order by sal)
里已经有排序的语句了，如果再在句尾添加排序子句，一致倒罢了，不一致，结果就令人费劲了。如：
SQL> select deptno,ename,sal,sum(sal) over (partition by deptno order by sal) dept_sum,
2 sum(sal) over (order by deptno,sal) sum
3 from emp
4 order by deptno desc;
??? DEPTNO ENAME???????????? SAL?? DEPT_SUM??????? SUM
---------- ---------- ---------- ---------- ----------
??????? 30 JAMES???????????? 950??????? 950????? 20575
?????????? WARD???????????? 1250?????? 3450????? 23075
?????????? MARTIN?????????? 1250?????? 3450????? 23075
?????????? TURNER?????????? 1500?????? 4950????? 24575
?????????? ALLEN??????????? 1600?????? 6550????? 26175
?????????? BLAKE??????????? 2850?????? 9400????? 29025
??????? 20 SMITH???????????? 800??????? 800?????? 9550
?????????? ADAMS??????????? 1100?????? 1900????? 10650
?????????? JONES??????????? 2975?????? 4875????? 13625
?????????? SCOTT??????????? 3000????? 10875????? 19625
?????????? FORD???????????? 3000????? 10875????? 19625
??????? 10 MILLER?????????? 1300?????? 1300?????? 1300
?????????? CLARK??????????? 2450?????? 3750?????? 3750
?????????? KING???????????? 5000?????? 8750?????? 8750
已选择14行
==================================================================
利用over实现的分页功能：
--假设code1,code2为用来分页的KEY，每页显示5第数据
select code1,code2,code3,
ceil(count(*) over(partition by code1,code2 order by rownum)/5),?
count(*) over(partition by code1,code2)
from ma_kbn order by code1,code2
