如何在Oracle10g中按顺序连接多行顺序 [英] How to concatenate multiple rows order by sequence in Oracle10g
问题描述
如果我有这样的数据:
GROUP | SEQUENCE | COMMAND
------------------------------
ONE | 3 | <message2>MESSAGE</message2>
ONE | 1 | <?xml version="1.0" encoding="UTF-8"?>
ONE | 2 | <message1>MESSAGE</message1>
TWO | 2 | <message2>MESSAGE</message2>
TWO | 1 | <?xml version="1.0" encoding="UTF-8"?>
........
TWO | 10 | <message9>MESSAGE</message9>
如何将命令连接成这样:
How can I concatenate the command to be like this:
GROUP | COMMAND
-----------------
ONE | <?xml version="1.0" encoding="UTF-8"?>,<message1>MESSAGE</message1>,<message2>MESSAGE</message2>
TWO | <?xml version="1.0" encoding="UTF-8"?>,<message1>MESSAGE</message1>, .. ,<message9>MESSAGE</message9>
我在下面使用了此查询,但根据其序列号,命令列的顺序不正确:
I used this query below but the command column is not in order according to their sequence number:
SELECT GROUP, WM_CONCAT(COMMAND) AS COMMAND
FROM (SELECT GROUP, SEQUENCE, COMMAND FROM TBL ORDER BY SEQUENCE)
GROUP BY GROUP
//AND THIS
SELECT GROUP, WM_CONCAT(DISTINCT COMMAND) AS COMMAND
FROM (SELECT GROUP, SEQUENCE, COMMAND FROM TBL ORDER BY SEQUENCE)
GROUP BY GROUP
任何建议都将不胜感激. ^ _ ^
Any advice and suggestions will be greatly appreciated. ^_^
推荐答案
请勿使用WM_CONCAT
.阅读为什么不使用WM_CONCAT函数甲骨文?
请参阅本主题 https://stackoverflow.com/a/28758117/3989608 .
它没有文档,依赖于WM_CONCAT
的任何应用程序一旦升级到12c
都将无法工作,因为它已从最新的12c版本中删除.
It is undocumented, and any application which relies on WM_CONCAT
will not work once upgraded to 12c
because it has been removed from the latest 12c version.
根据数据库版本,有很多方法可以进行字符串聚合.请参见下面的几个示例:
There are many ways of doing string-aggregation, depending on the database version. See few examples below:
11gR2
使用LIASTAGG
:
SQL> SELECT grp,
2 listagg(command, ',') WITHIN GROUP(
3 ORDER BY seq) command
4 FROM t
5 GROUP BY grp;
GRP COMMAND
--- --------------------------------------------------------------------------------------------
ONE <?xml version=1.0 encoding=UTF-8?>,<message1>MESSAGE</message1>,<message2>MESSAGE</message2>
TWO <?xml version=1.0 encoding=UTF-8?>,<message2>MESSAGE</message2>,<message9>MESSAGE</message9>
SQL>
9i及更高版本
使用ROW_NUMBER()
和SYS_CONNECT_BY_PATH
:
SQL> SELECT grp,
2 LTRIM(MAX(SYS_CONNECT_BY_PATH(command,','))
3 KEEP (DENSE_RANK LAST ORDER BY seq),',') command
4 FROM (SELECT grp,
5 command,
6 seq,
7 ROW_NUMBER() OVER (PARTITION BY grp ORDER BY seq) AS curr,
8 ROW_NUMBER() OVER (PARTITION BY grp ORDER BY seq) -1 AS prev
9 FROM t)
10 GROUP BY grp
11 CONNECT BY prev = PRIOR curr AND grp = PRIOR grp
12 START WITH curr = 1;
GRP COMMAND
--- --------------------------------------------------------------------------------------------
ONE <?xml version=1.0 encoding=UTF-8?>,<message1>MESSAGE</message1>,<message2>MESSAGE</message2>
TWO <?xml version=1.0 encoding=UTF-8?>,<message2>MESSAGE</message2>,<message9>MESSAGE</message9>
SQL>
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