Oracle如何将一列的重复值分组到另一列

Question

我有一个 oracle VIEW，它在一列中包含一些重复值

myView : 

---------------------------
ID  | col 1       | col 2  |
---------------------------
1   | P1          |V1
2   | P1          |V1
3   | P1          |V2
4   | P1          |V3
5   | P2          |t1
6   | P2          |t1
7   | P2          |t2

我想基于 myView 创建另一个视图，其中包含如下值：

---

ID  | col 1       | col 2  |col 3
---------------------------------------
1   | P1          |V1      |V1,V1,V2,V3
2   | P1          |V1      |V1,V1,V2,V3
3   | P1          |V2      |V1,V1,V2,V3
4   | P1          |V3      |V1,V1,V2,V3
5   | P2          |t1      |t1,t1,t2
6   | P2          |t1      |t1,t1,t2
7   | P2          |t2      |t1,t1,t2

提前感谢您的帮助

Answer 1

你可以使用listagg()作为窗口函数：

select t.*,
       listagg(col2, ',') within group (order by col1) over (partition by col1) as col3s
from t;

Answer 2

select id, col1, col2, LISTAGG(col2, ',') WITHIN GROUP (ORDER BY col1) OVER (PARTITION BY col1) as col3 
from myView;