TYPE QTY CNT2
---------- ---------- ------------
3 1/2
1 6 2/2
2 5 1/3
7 2/3
2 9 3/3

SQL> select * from test;
---------- -------------------------------------------------
1 11111
2 22222
3 33333
4 44444

SQL> select t.id,mc,to_char(b.rn)||'/'||t.id)e
2 from test t,
(select rownum rn from (select max(to_number(id)) mid from test) connect by rownum <=mid ))L
4 where b.rn<=to_number(t.id)
order by id

ID MC TO_CHAR(B.RN)||'/'||T.ID
--------- -------------------------------------------------- ---------------------------------------------------
1 11111 1/1
2 22222 1/2
2 22222 2/2
3 33333 1/3
3 33333 2/3
3 33333 3/3
44444 1/4 44444 2/4
4 44444 3/4CNOUG4 44444 4/4

10 rows selected

*******************************************************************

关于partition by

这些都是分析函数，好像是8.0以后才有的 row_number()和rownum差不多，功能更强一点（可以在各个分组内从1开时排序） rank()是跳跃排序，有两个第二名时接下来就是第四名（同样是在各个分组内） dense_rank()l是连续排序，有两个第二名时仍然跟着第三名。相比之下row_number是没有重复值的 lag（arg1,arg2,arg3): arg1是从其他行返回的表达式 arg2是希望检索的当前行分区的偏移量。是一个正的偏移量，时一个往回检索以前的行的数目。 arg3是在arg2表示的数目超出了分组的范围时返回的值。

1.
select deptno,row_number() over(partition by deptno order by sal) from emp order by deptno;
2.
select deptno,rank() over (partition by deptno order by sal) from emp order by deptno;
3.
select deptno,dense_rank() over(partition by deptno order by sal) from emp order by deptno;
4.
select deptno,ename,sal,lag(ename,1,null) over(partition by deptno order by ename) from emp ord er by deptno;
5.
select deptno,ename,sal,lag(ename,2,'example') over(partition by deptno order by ename) from em p
order by deptno;
6.
select deptno, sal,sum(sal) over(partition by deptno) from emp;--每行记录后都有总计值 select deptno, sum(sal) from emp group by deptno;
7. 求每个部门的平均工资以及每个人与所在部门的工资差额

select deptno,ename,sal ,
round(avg(sal) over(partition by deptno)) as dept_avg_sal,
round(sal-avg(sal) over(partition by deptno)) as dept_sal_diff
from emp;