很多情況下，我們有必要把樹形結構進行資料梳理。比如，要方便的過濾出一個父節點下的所有子節點等等。。。

這個時候，我們可以生成一個路徑表字符串，在應用時只需要對該字串進行索引即可達成目的。

目標：按圖示的部門結構樹，獲取本身的完整路徑字串。比如，前道工序部門，其部門程式碼為PDTE，上級部門為PD生產部，按結構樹獲取到一個/PD/PDTE/的字串。

　　先來一個簡單點的展示：

WITH T AS (SELECT     CAST('/' + DeptCode + '/' AS NVARCHAR(MAX)) AS DpPath, DeptRKEY AS DpKey
                         FROM          Base_Department
                         WHERE      (ILevel = 1)--指定父級起點
                         UNION ALL
                         SELECT     CAST(t.DpPath + D.DeptCode + '/' AS NVARCHAR(MAX)) AS DpPath, D.DeptRKEY AS DpKey
                         FROM         Base_Department AS D INNER JOIN
                                               T ON D.ParentRKEY = T.DpKey)--設定遞迴關聯
    SELECT     DpPath, DpKey     FROM         T--輸出結果

　　輸出如下圖：

　　然後開個稍微複雜點的，帶上級機構關聯上：

WITH T AS (SELECT     '/' + CAST(DeptCode AS NVARCHAR(MAX)) + '/' AS DpPath, DeptRKEY AS DpKey, DeptNameLL AS DpNameLL, DeptNameLI AS DpNameLI, ILevel AS DpLevel, ISEQ AS DpSEQ, 
                                                BranchRKEY
                         FROM          Base_Department
                         WHERE      (ILevel = 1)
                         UNION ALL
                         SELECT     CAST(t.DpPath + D.DeptCode + '/' AS NVARCHAR(MAX)) AS DpPath, D.DeptRKEY AS DpKey, D.DeptNameLL AS DpNameLL, D.DeptNameLI AS DpNameLI, D.ILevel AS DpLevel, 
                                               D.ISEQ AS DpSEQ, D.BranchRKEY
                         FROM         Base_Department AS D INNER JOIN
                                               T ON D.ParentRKEY = T.DpKey)
    SELECT     '/' + BranchCode + '/' AS DpPath, BranchCode AS DpKey, BranchNameLL AS DpNameLL, BranchNameLI AS DpNameLI, 0 AS DpLevel, 0 AS DpSEQ
     FROM         Base_Branch
UNION ALL
SELECT     '/' + B.BranchCode + T.DpPath AS Expr1, STR(T.DpKey) AS DpKey, T.DpNameLL, T.DpNameLI, T.DpLevel, T.DpSEQ
FROM         T INNER JOIN
                      Base_Branch AS B ON T.BranchRKEY = B.BranchRKEY

　　輸出如下：

　　如果，某些場合下，就能很好的利用這個DpPath了。