带OPTION的无限循环CTE（maxrecursion 0）

Question

我有CTE查询，其上有大量记录。以前它工作得很好。但是最近，它会因一些成员

终止该语句错误。报表完成前，最大递归100已用尽。

所以我把OPTION (maxrecursion 0)或OPTION (maxrecursion 32767)我的查询，因为我不希望限制的记录。但是，结果是查询需要永久加载。我该如何解决这个问题？

这里是我的代码：

with cte as(
-- Anchor member definition 
    SELECT e.SponsorMemberID , e.MemberID, 1 AS Level 
    FROM tblMember AS e 
    where e.memberid = @MemberID 

union all 

-- Recursive member definition 
    select child.SponsorMemberID , child.MemberID, Level + 1 
    from tblMember child 

join cte parent 

on parent.MemberID = child.SponsorMemberID 
) 
-- Select the CTE result 
    Select distinct a.* 
    from cte a 
    option (maxrecursion 0) 

编辑：删除不必要的代码，很容易理解

解决：所以问题不是来自maxrecursion。它来自CTE。我不知道为什么，但可能它包含任何赞助商周期：A - > B - > C - > A - > ...（感谢@HABO）

我试过这种方法，它的工作原理。 Infinite loop in CTE when parsing self-referencing table

Answer 1

如果您正在达到递归限制，您可能在赞助关系或数据循环中具有相当的深度。像下面这样的查询将检测循环并终止递归：

declare @tblMember as Table (MemberId Int, SponsorMemberId Int); 
insert into @tblMember (MemberId, SponsorMemberId) values 
    (1, 2), (2, 3), (3, 5), (4, 5), (5, 1), (3, 3); 
declare @MemberId as Int = 3; 
declare @False as Bit = 0, @True as Bit = 1; 

with Children as (
    select MemberId, SponsorMemberId, 
    Convert(VarChar(4096), '>' + Convert(VarChar(10), MemberId) + '>') as Path, @False as Loop 
    from @tblMember 
    where MemberId = @MemberId 
    union all 
    select Child.MemberId, Child.SponsorMemberId, 
    Convert(VarChar(4096), Path + Convert(VarChar(10), Child.MemberId) + '>'), 
    case when CharIndex('>' + Convert(VarChar(10), Child.MemberId) + '>', Path) = 0 then @False else @True end 
    from @tblMember as Child inner join 
     Children as Parent on Parent.MemberId = Child.SponsorMemberId 
    where Parent.Loop = 0) 
    select * 
    from Children 
    option (MaxRecursion 0);