无法使用 LISTAGG

Not able to use LISTAGG(无法使用 LISTAGG)

问题描述

SELECT deptno, LISTAGG(ename, ',') WITHIN GROUP (ORDER BY ename) AS employees
FROM   emp
GROUP BY deptno;

Error:- 
ORA-00923: FROM keyword not found where expected
00923. 00000 -  "FROM keyword not found where expected"
*Cause:    
*Action:
Error at Line: 1 Column: 42

Oracle 数据库 11g 企业版 11.1.0.7.0 版 - 64 位生产

Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production

推荐答案

在 这篇文章您有不同的方法来处理字符串聚合，如果您运行的是 11g 第 2 版之前的 Oracle 版本(这是您的场景)，则需要考虑这些方法.

In this article you have different approaches to dealing with string aggegation, including those to take into account if you are running an Oracle version prior to 11g Release 2 (which is your scenario).

特别是可以使用Oracle的WM_CONCAT函数:

Particularly, you can use Oracle's WM_CONCAT function:

SELECT deptno, wm_concat(ename) AS employees
FROM   emp
GROUP BY deptno;

您还可以为字符串聚合定义自己的函数或使用其他函数，例如 SYS_CONNECT_BY_PATH 或 COLLECT.在上面的文章中，您有这些方法的示例.

You can also define your own function for string aggregation or use other functions such as SYS_CONNECT_BY_PATH or COLLECT. In the above article you have examples of these methods.

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