将错误视为"ORA-32044: cycle detected while executing recursive WITH query"

Question

我得到错误

ORA-32044:在执行递归WITH查询时检测到循环

在Oracle中执行以下查询。

WITH EmpsCTE (affiliation_id, from_customer_id,to_customer_id, to_name, level1)
AS
(
SELECT affiliation_id, from_customer_id,to_customer_id, to_name, 0
 FROM affiliation aff
 WHERE to_customer_id != from_customer_id
 and to_customer_id = 1000022560394
UNION ALL
SELECT aff.affiliation_id, aff.from_customer_id,aff.to_customer_id, aff.to_name, m.level1 + 1
 FROM affiliation aff
 INNER JOIN EmpsCTE  m
 ON aff.to_customer_id = m.from_customer_id
)
SELECT * FROM EmpsCTE;

Answer 1

除了一个数据条件外，您的代码将正常工作，即当您的to_customer(1000022560394)自己首先启动事务并且在某些级别的事务之后仅将其返回给他时。

- - - - - -样本数据集

在这种情况下，即使在事务结束时，查询的递归部分也会发现它的所有条件都为真，因为数据将同时存在于正常表和增量数据集中。

一个解决方案是创建一个匹配标志来确定它的相遇次数，避免无限循环:

WITH EmpsCTE (affiliation_id, from_customer_id,to_customer_id, to_name,level1,match_count)  
AS  
(  
SELECT affiliation_id, from_customer_id,to_customer_id, to_name, 0, 0 match_count  
 FROM affiliation aff  
 WHERE to_customer_id != from_customer_id  
 and to_customer_id = 1000022560394  
UNION ALL  
SELECT aff.affiliation_id, aff.from_customer_id,aff.to_customer_id, aff.to_name, m.level1 + 1,1 match_count  
 FROM affiliation aff  
 INNER JOIN EmpsCTE  m  
 ON aff.to_customer_id = m.from_customer_id  
 where m.match_count=0  
)  
SELECT * FROM EmpsCTE;