sql - 将多个列值合并为一个并在多行中打印一个字符串 - oracle SQL

Question

我不知道从哪里开始这个查询。Stuff() 函数无助于获得我想要的结果。任何帮助表示赞赏。

我的桌子：

+-----+-----------+--------+
| uid |   uname   |  host  |
+-----+-----------+--------+
|   1 | testuser  | host 1 |
|   2 | testuser  | host 2 |
|   3 | testuser2 | host 3 |
|   4 | testuser2 | host 4 |
+-----+-----------+--------+

预期输出：

+-----+-----------+--------+---------------+
| uid |   uname   |  host  | combined host |
+-----+-----------+--------+---------------+
|   1 | testuser  | host 1 | host1,host2   |
|   2 | testuser  | host 2 | host1,host2   |
|   3 | testuser2 | host 3 | host3,host4   |
|   4 | testuser2 | host 4 | host3,host4   |
+-----+-----------+--------+---------------+

标签： sqloracleoracle11goracle11gr2

Answer 1

使用LISTAGG和子查询连接

    with cte as
(
select 1  uid1 ,'testuser' as uname,'host 1' as host from DUAL union all
select 2  uid1 ,'testuser' as uname,'host 2' as host from DUAL union all
select 3  uid1 ,'testuser2' as uname,'host 3' as host from DUAL union all
select 4  uid1 ,'testuser2' as uname,'host 4' as host from DUAL

)
  select cte.uname,cte.host,val from cte join (
 select uname,LISTAGG(host,',') within group (order by host) as val
 from cte group by uname) t on cte.uname=t.uname

dmeo 链接

UNAME       HOST          VAL
testuser    host 1  host 1,host 2
testuser    host 2  host 1,host 2
testuser2   host 3  host 3,host 4
testuser2   host 4  host 3,host 4