oracle wmsys.wm_concat 问题

[jya126]

我建个表 t,字段为key,name
数据有：1,a;
1,b;
2,a;
2,b;
2,c;
我用：select t.key,wmsys.wm_concat(t.name) from t order by t.key
结果会成为：1 a,b;
2 c,a,b;
我想问下有没有方法使其第二行变为： 2 a,b,c ，也就是能排下序

[真的不知道取什么名]

select t.key,wmsys.wm_concat(t.name) 
from (select * from t order by key) t
group by t.key 

[碧水幽幽泉]

[Quote=引用 1 楼 zhuomingwang 的回复:]
SQL code

select t.key,wmsys.wm_concat(t.name)
from (select * from t order by key) t
group by t.key
[/Quote]
先排序，再行转列！

[心中的彩虹]

[Quote=引用楼主 jya126 的回复:]
我建个表 t,字段为key,name
数据有：1,a;
1,b;
2,a;
2,b;
2,c;
我用：select t.key,wmsys.wm_concat(t.name) from t order by t.key
结果会成为：1 a,b;
2 c,a,b;
我想问下有没有方法使其第二行变为： 2 a,b,c ，也就是能排下序
[/Quote]

select key,wmsys.wm_concat(name) from (
select t.key,t.name from t order by t.key,t.name  
) group by key

[gelyon]

--wm_concat函数其实也是一个开窗函数，因此直接套用分析函数就可以了
select t.key,wmsys.wm_concat(t.name)over(partition by t.key order by t.name) from t order by t.key 

[lxyzxq2008]

paddy的外面再套一层
minitoy正解～～～

with tab as
(select 1 key, 'a' name from dual union all
select 1,'b' from dual union all
select 2,'a' from dual union all
select 2,'b' from dual union all select 2,'c' from dual)

SELECT key, MAX(NAME) NAME
  FROM (SELECT t.key,
               wmsys.wm_concat(t.NAME) over(PARTITION BY t.key ORDER BY t.NAME) NAME
          FROM tab t)
 GROUP BY key;
------------------------------------------------------------------
1	a,b
2	a,b,c

[minitoy]

只有这个能确保排序,不过记得要套一层取max[Quote=引用 4 楼 gelyon 的回复:]
SQL code

--wm_concat函数其实也是一个开窗函数，因此直接套用分析函数就可以了
select t.key,wmsys.wm_concat(t.name)over(partition by t.key order by t.name) from t order by t.key
[/Quote]

[minitoy]

SELECT key, MAX(NAME) NAME
  FROM (SELECT t.key,
               wmsys.wm_concat(t.NAME) over(PARTITION BY t.key ORDER BY t.NAME) NAME
          FROM t)
 GROUP BY key;