在不创建存储过程的情况下，如何在oracle中实现以下功能？
数据集:
question_id element_id
1 7
1 8
2 9
3 10
3 11
3 12
预期结果:
question_id element_id
1 7,8
2 9
3 10,11,12
有很多方法可以进行字符串聚合，但最简单的是用户定义的函数.Try this for a way that does not require a function.作为一个注释，没有这个功能就没有简单的方法.
这是没有自定义函数的最短路径:(它使用ROW_NUMBER()和SYS_CONNECT_BY_PATH函数)
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;