在不创建存储过程的情况下，如何在Oracle中将多行串联在一起? [英] How can multiple rows be concatenated into one in Oracle without creating a stored procedure?

问题描述

如何在不创建存储过程的情况下在oracle中实现以下目标?

How can I achieve the following in oracle without creating a stored procedure?

数据集:

question_id    element_id
1              7
1              8
2              9
3              10
3              11
3              12

所需结果:

question_id    element_id
1              7,8
2              9
3              10,11,12

推荐答案

有很多方法可以进行字符串聚合，但是最简单的方法是用户定义的函数. 尝试这种方法不需要功能. ，没有该功能就没有简单的方法.

There are many way to do the string aggregation, but the easiest is a user defined function. Try this for a way that does not require a function. As a note, there is no simple way without the function.

这是没有自定义函数的最短路由:(它使用ROW_NUMBER()和SYS_CONNECT_BY_PATH函数)

This is the shortest route without a custom function: (it uses the ROW_NUMBER() and SYS_CONNECT_BY_PATH functions )

SELECT questionid,
       LTRIM(MAX(SYS_CONNECT_BY_PATH(elementid,','))
       KEEP (DENSE_RANK LAST ORDER BY curr),',') AS elements
FROM   (SELECT questionid,
               elementid,
               ROW_NUMBER() OVER (PARTITION BY questionid ORDER BY elementid) AS curr,
               ROW_NUMBER() OVER (PARTITION BY questionid ORDER BY elementid) -1 AS prev
        FROM   emp)
GROUP BY questionid
CONNECT BY prev = PRIOR curr AND questionid = PRIOR questionid
START WITH curr = 1;

这篇关于在不创建存储过程的情况下，如何在Oracle中将多行串联在一起?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！