使用選項（MAXRECURSION 0）

Question

我有以下在分層數據上運行的 sql 查詢：

WITH DirectReports(RootId, ManagerId, Id, RelativeEmployeeLevel) AS
(
    SELECT Id RootId, ManagerId, Id, 0 AS RelativeEmployeeLevel
    FROM tbl    
    UNION ALL
    SELECT d.RootId, e.ManagerId, e.Id, RelativeEmployeeLevel + 1
    FROM tbl AS e
        INNER JOIN DirectReports AS d
        ON e.ManagerId = d.Id   
), q2 as
(
    SELECT RootId,
           ManagerId,
           Id,           
           RelativeEmployeeLevel,
           max(RelativeEmployeeLevel) over (partition by RootId) - RelativeEmployeeLevel LevelsBelow
    FROM DirectReports  
)

SELECT * FROM q2 where rootid = Id

在運行此程序時，我看到此錯誤：'語句終止。 最大遞歸 100 在語句完成之前已經用完'

我更新了查詢以包括：

選項（最大遞歸 0）

WITH DirectReports(RootId, ManagerId, Id, RelativeEmployeeLevel) AS
(
    SELECT Id RootId, ManagerId, Id, 0 AS RelativeEmployeeLevel
    FROM tbl    
    UNION ALL
    SELECT d.RootId, e.ManagerId, e.Id, RelativeEmployeeLevel + 1
    FROM tbl AS e
        INNER JOIN DirectReports AS d
        ON e.ManagerId = d.Id   
), q2 as
(
    SELECT RootId,
           ManagerId,
           Id,           
           RelativeEmployeeLevel,
           max(RelativeEmployeeLevel) over (partition by RootId) - RelativeEmployeeLevel LevelsBelow
    FROM DirectReports  
    OPTION (MAXRECURSION 0)
)

SELECT * FROM q2 where rootid = Id

我看到一個錯誤：關鍵字“OPTION”附近的語法不正確

我錯過了什么？

Answer 1

您正在嘗試使用遞歸 CTE 從每個員工開始返回組織的自上而下視圖。 我懷疑每個員工都處於組織的最高層。 如果是的話，就沒有理由這樣做了。 我的猜測是頂部有一個人。

在沒有OPTION(MAXRECURSION = 0)的情況下先試試這個。 我無法想象你有超過 100 層的管理層。

WITH DirectReports(RootId, ManagerId, Id, RelativeEmployeeLevel) AS
(
    SELECT Id RootId, ManagerId, Id, 0 AS RelativeEmployeeLevel
    FROM tbl
WHERE EmployeeName = 'Head Honcho'
    UNION ALL
    SELECT d.RootId, e.ManagerId, e.Id, RelativeEmployeeLevel + 1
    FROM tbl AS e
        INNER JOIN DirectReports AS d
        ON e.ManagerId = d.Id   
), q2 as
(
    SELECT RootId,
           ManagerId,
           Id,           
           RelativeEmployeeLevel,
           max(RelativeEmployeeLevel) over (partition by RootId) - RelativeEmployeeLevel LevelsBelow
    FROM DirectReports  
)

SELECT * FROM q2 where rootid = Id