使用 SQL 查询的树视图

Question

我有一个区域表，我想要一个树视图（表简单排序为树）是否可以使用 sql 查询帮助表示赞赏，我尝试使用自连接来实现，但我没有得到想要的结果。

树视图是这样的

个人

• Div1
• • Zon1
• div2
• • zon2
• div3
• • zon3

编辑：

根据 Charles Bretana 的建议，我在下面的查询中尝试了 CTE，但它没有给我想要的结果。

WITH Emp_CTE (id, ParentID, name)
AS (
SELECT id, ParentID, name
FROM eQPortal_Region
WHERE ParentID=0
UNION ALL
SELECT e.id, e.ParentID, e.name
FROM eQPortal_Region e
INNER JOIN Emp_CTE ecte ON ecte.id = e.ParentID
)
SELECT *
FROM Emp_CTE
GO

这是结果..出了什么问题？

InDiv1

• Div1
• Div2
• Div3
• • Zon3
• • Zon2
• • zon1

Answer 1

这家伙Maulik Dhorajia完美地回答了这个问题......

http://maulikdhorajia.blogspot.com/2012/06/sql-server-using-ctecommon-table.html

制作了查询的副本..

;WITH CTECompany
AS
(
    SELECT 
    ID, 
    ParentID, 
    Name , 
    0 AS HLevel,
    CAST(RIGHT(REPLICATE('_',5) +  CONVERT(VARCHAR(20),ID),20) AS VARCHAR(MAX)) AS OrderByField
FROM Region
WHERE ParentID = 0

UNION ALL

SELECT 
    C.ID, 
    C.ParentID, 
    C.Name , 
    (CTE.HLevel + 1) AS HLevel,
    CTE.OrderByField + CAST(RIGHT(REPLICATE('_',5) +  CONVERT(VARCHAR(20),C.ID),20) AS VARCHAR(MAX)) AS OrderByField
FROM Region C
INNER JOIN CTECompany CTE ON CTE.ID = C.ParentID
WHERE C.ParentID IS NOT NULL


)

-- Working Example
SELECT 
ID
, ParentID
, HLevel
, Name
, (REPLICATE( '----' , HLevel ) + Name) AS Hierachy
FROM CTECompany
ORDER BY OrderByField

Answer 2

请参阅以下示例 SQL 脚本：

DECLARE @lV NCHAR(1)=NCHAR(9474),@lR NCHAR(1)=NCHAR(9500),@lU NCHAR(1)=NCHAR(9492),@spc NCHAR(1)='　';
WITH data AS(SELECT * FROM(VALUES(1,'0','In Div1',1),(2,'1','Div1',1),(3,'2','zon1',1),(4,'1','Div2',2),(5,'1','Div3',3),(6,'4','Zon2',1),(7,'5','Zon3',1))t([ID],[ParentID],[Name],[SeqOrder])
),d_root AS(SELECT CAST('/'AS NVARCHAR(MAX))[n_path],* FROM data WHERE ParentID='0'
),d_cte AS(SELECT b.n_path+CAST(ROW_NUMBER()OVER(ORDER BY a.ID)AS NVARCHAR(MAX))+'/'[n_path],a.* FROM data a INNER JOIN d_root b ON a.ParentID=b.ID UNION ALL SELECT b.n_path+CAST(ROW_NUMBER()OVER(ORDER BY a.ID)AS NVARCHAR(MAX))+'/'[n_path],a.* FROM data A INNER JOIN d_cte b ON a.ParentID=b.ID
),Tree_BASE AS (SELECT CAST(n_path AS HIERARCHYID)[h_id],* FROM d_root UNION ALL SELECT CAST(n_path AS HIERARCHYID)[h_id],* FROM d_cte
),cte_o AS(SELECT a.h_id,CASE WHEN EXISTS(SELECT * FROM Tree_BASE WHERE h_id>b.h_id AND h_id.GetAncestor(1)=b.h_id.GetAncestor(1))THEN @lV ELSE @spc END[t_l] FROM Tree_BASE a INNER JOIN Tree_BASE b ON a.h_id.IsDescendantOf(b.h_id)=1 AND NOT b.h_id=HIERARCHYID::GetRoot()
),cte_m AS(SELECT x.*,(SELECT t_l+'' FROM cte_o WHERE h_id=x.h_id FOR XML PATH(''))[b_tree] FROM Tree_BASE x
),cte_h AS(SELECT ISNULL(LEFT(b_tree,LEN(b_tree)-1)+CASE WHEN EXISTS(SELECT * FROM Tree_BASE WHERE h_id>a.h_id AND h_id.GetAncestor(1)=a.h_id.GetAncestor(1))THEN @lR ELSE @lU END,'')+' '+RTRIM(Name) [TreeV],a.h_id FROM cte_m a
)SELECT b.TreeV,ROW_NUMBER()OVER(ORDER BY a.h_id ASC)[row_id]FROM Tree_BASE a INNER JOIN cte_h b ON a.h_id=b.h_id ORDER BY row_id