如何找到导致 ORA-01436 错误的数据

Question

我有一个查询要查看数据的父子层次列表。在运行下面的查询中，我得到了错误 ORA-01436。

SELECT ParentPropertyRSN, CONNECT_BY_ROOT PropertyRSN as PropertyRSN,
   LEVEL, SYS_CONNECT_BY_PATH(ParentPropertyRSN, '/') Path
FROM Property
   CONNECT BY PRIOR PropertyRSN = ParentPropertyRSN
   order by level desc;

所以我在 CONNECT BY 子句中添加了 NOCYCLE 并获得了完整的数据列表及其层次结构路径

现在我需要的是一个查询来获取导致 ORA-01436.

数据不准确的行的列表

Answer 1

你确实应该使用 NOCYCLE 来避免无限循环。最重要的是，您可以使用 CONNECT_BY_ISCYCLE 来识别有问题的行：

SELECT 
    ParentPropertyRSN, 
    CONNECT_BY_ROOT PropertyRSN as PropertyRSN,
    LEVEL, 
    SYS_CONNECT_BY_PATH(ParentPropertyRSN, '/') Path,
    CONNECT_BY_ISCYCLE Has_Cycle
FROM Property
CONNECT BY NOCYCLE PRIOR PropertyRSN = ParentPropertyRSN
ORDER BY level desc;

来自 the documentation:

The CONNECT_BY_ISCYCLE pseudocolumn returns 1 if the current row has a child which is also its ancestor. Otherwise it returns 0.

You can specify CONNECT_BY_ISCYCLE only if you have specified the NOCYCLE parameter of the CONNECT BY clause. NOCYCLE enables Oracle to return the results of a query that would otherwise fail because of a CONNECT BY loop in the data.

如何找到导致 ORA-01436 错误的数据

How to find the imporper data that cause ORA-01436

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