在语句完成之前,最大递归100已用尽

Question

我不断得到max recursion error这个查询.

起初我以为是因为返回null然后它会尝试匹配导致错误的空值,但是我重写了我的查询,因此不返回空值并且仍然会发生错误.

什么是重写此函数的最佳方法,以便不会发生错误

WITH EmployeeTree AS
(
    SELECT 
        EMP_SRC_ID_NR Id, USR_ACV_DIR_ID_TE Uuid, 
        CASE Employees.APV_MGR_EMP_ID 
           WHEN Null THEN '0' 
           ELSE Employees.APV_MGR_EMP_ID 
        END as  ApprovalManagerId 
    FROM 
        dbo.[tEmployees] as Employees WITH (NOLOCK)
    WHERE 
        APV_MGR_EMP_ID = @Id 
        and Employees.APV_MGR_EMP_ID is not null 
        and Employees.EMP_SRC_ID_NR is not null  

    UNION ALL

    SELECT 
        EMP_SRC_ID_NR Id, USR_ACV_DIR_ID_TE Uuid, 
        CASE Employees.UPS_ACP_EMP_NR 
           WHEN Null THEN '1' 
           ELSE Employees.UPS_ACP_EMP_NR 
        END as ApprovalManagerId 
    FROM 
        dbo.[tEmployees] as Employees WITH (NOLOCK)
    WHERE 
        UPS_ACP_EMP_NR = @Id 
        and Employees.APV_MGR_EMP_ID is not null 
        and Employees.EMP_SRC_ID_NR is not null  

    UNION ALL

    SELECT 
        Employees.EMP_SRC_ID_NR, Employees.USR_ACV_DIR_ID_TE, 
        CASE Employees.APV_MGR_EMP_ID 
            WHEN Null THEN '2' 
            ELSE Employees.APV_MGR_EMP_ID 
        END  
    FROM 
        dbo.[tEmployees] as Employees WITH (NOLOCK)
    JOIN 
        EmployeeTree ON Employees.APV_MGR_EMP_ID = EmployeeTree.Id 
    where  
        Employees.APV_MGR_EMP_ID is not null 
        and Employees.EMP_SRC_ID_NR is not null             
)
SELECT 
    Id AS [EmployeeId], 
    Uuid AS [EmployeeUuid], 
    ApprovalManagerId AS [ManagerId] 
FROM EmployeeTree        

Answer 1

在查询末尾指定maxrecursion选项:

...
from EmployeeTree
option (maxrecursion 0)

这允许您指定CTE在生成错误之前可以递归的频率.Maxrecursion 0允许无限递归.

Answer 2

它只是一个避免最大递归错误的示例.我们必须使用选项(maxrecursion 365); 或选项(maxrecursion 0);

DECLARE @STARTDATE datetime; 
DECLARE @EntDt datetime; 
set @STARTDATE = '01/01/2009';  
set @EntDt = '12/31/2009'; 
declare @dcnt int; 
;with DateList as   
 (   
    select @STARTDATE DateValue   
    union all   
    select DateValue + 1 from    DateList      
    where   DateValue + 1 < convert(VARCHAR(15),@EntDt,101)   
 )   
  select count(*) as DayCnt from (   
  select DateValue,DATENAME(WEEKDAY, DateValue ) as WEEKDAY from DateList
  where DATENAME(WEEKDAY, DateValue ) not IN ( 'Saturday','Sunday' )     
  )a
option (maxrecursion 365);