语句完成前已用尽最大递归100

136

我不断得到max recursion error这个查询。

起初我以为是因为返回了null，然后它会尝试与null值匹配，从而导致错误，但是，我重写了查询，因此不返回null并仍然发生错误。

什么是重写此功能的最佳方法，这样就不会发生错误

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

sql stored-procedures common-table-expression

— 帮我
source

此行可以替换为COALESCE()：

CASE Employees.APV_MGR_EMP_ID             WHEN Null THEN '0'             ELSE Employees.APV_MGR_EMP_ID          END as  ApprovalManagerId

=COALESCE(Employees.APV_MGR_EMP_ID, 0) AS ApprovalManagerID

— David Faber

Answers:

249

在查询末尾指定maxrecursion选项：

...
from EmployeeTree
option (maxrecursion 0)

这样，您可以指定CTE在产生错误之前可以递归的频率。Maxrecursion 0允许无限递归。

— 安多玛
source

嗯，这

— 行得通，

@bugz Maxrecursion 0现在确实会影响您的查询，您是否需要在其他地方查找问题

— t-clausen.dk 2012年

嗯，这是我数据中的循环

— 引用

+1我使用此选项来调试类似的问题。如果查询是无限递归的，则在执行查询后必须在Management Studio中取消该查询，否则服务器将假脱机执行行，直到客户端内存不足。

— Iain Samuel McLean年长者，

虽然这可能在您希望查询进行很深的递归的情况下解决了该问题，但它可能只是掩盖了查询中的问题。

— Christian Findlay'7

它只是避免最大递归误差的示例。我们必须使用选项（maxrecursion 365）; 或选项（最大递归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);

— 牟
source