CTE 查询。声明终止。最大递归 100 在语句完成之前已经用完

Question

在此 sql 查询中，现在面临以下错误

The statement terminated. The maximum recursion 100 has been exhausted before statement completion.

WITH rCTE AS(
    SELECT H.Person,
           H.AssignedTo,
           H.Person AS NextPerson,
           H.AssignedTo AS NextAssignedTo,
           CONVERT(nvarchar(4000),CONCAT('|',H.AssignedTo,'|')) AS ExpectedResult,
           1 AS Level
    FROM dbo.tblHierarchy H
    UNION ALL      
    SELECT r.Person,
           r.AssignedTo,
           H.Person AS NextPerson,
           H.AssignedTo AS NextAssignedTo,
           CONVERT(nvarchar(4000),CONCAT(r.Expectedresult,H.AssignedTo,'|')),
           Level + 1
    FROM dbo.tblHierarchy H
         JOIN rCTE r ON r.NextAssignedTo = H.Person),
RNs AS(
    SELECT r.Person,
           r.AssignedTo,
           r.ExpectedResult,
           ROW_NUMBER() OVER (PARTITION BY r.Person ORDER BY r.level DESC) AS RN
    FROM rCTE r)
SELECT RN.Person,
       RN.AssignedTo,
       RN.ExpectedResult
FROM RNs RN
WHERE RN = 1
ORDER BY RN.Person;

不确定在上面的查询中添加 选项 (maxrecursion 0) 的位置以消除此错误。

Answer 1

默认递归导致的错误是100，但你的查询可能不止于此，你可以尝试在查询的末尾添加这个提示

The server-wide default is 100. When 0 is specified, no limit is applied. Only one MAXRECURSION value can be specified per statement. For more information

如果您期望递归深度最大，我会为此设置一个数字而不是 0。

WITH rCTE AS(
    SELECT H.Person,
           H.AssignedTo,
           H.Person AS NextPerson,
           H.AssignedTo AS NextAssignedTo,
           CONVERT(nvarchar(4000),CONCAT('|',H.AssignedTo,'|')) AS ExpectedResult,
           1 AS Level
    FROM dbo.tblHierarchy H
    UNION ALL      
    SELECT r.Person,
           r.AssignedTo,
           H.Person AS NextPerson,
           H.AssignedTo AS NextAssignedTo,
           CONVERT(nvarchar(4000),CONCAT(r.Expectedresult,H.AssignedTo,'|')),
           Level + 1
    FROM dbo.tblHierarchy H
         JOIN rCTE r ON r.NextAssignedTo = H.Person),
RNs AS(
    SELECT r.Person,
           r.AssignedTo,
           r.ExpectedResult,
           ROW_NUMBER() OVER (PARTITION BY r.Person ORDER BY r.level DESC) AS RN
    FROM rCTE r)
SELECT RN.Person,
       RN.AssignedTo,
       RN.ExpectedResult
FROM RNs RN
WHERE RN = 1
ORDER BY RN.Person
option (maxrecursion 0);

CTE 查询。声明终止。最大递归 100 在语句完成之前已经用完

CTE Query. The statement terminated. The maximum recursion 100 has been exhausted before statement completion

sql

sql-server