Question

我有一个表类别，

1）Id
2）CategoryName
3）CategoryMaster

数据为：

1台电脑0
2软件1
3多媒体1
4动画3
5健康0
6 Healthsub 5

我创建了递归查询：

 ;WITH CategoryTree AS
 (
  SELECT *, CAST(NULL AS VARCHAR(50)) AS ParentName, 0 AS Generation    
  FROM dbo.Category    
  WHERE CategoryName = 'Computers'

  UNION ALL        

  SELECT Cat.*,CategoryTree.CategoryName AS ParentName, Generation + 1    
  FROM dbo.Category AS Cat  INNER JOIN 
  CategoryTree ON Cat.CategoryMaster = CategoryTree.Id
 )

 SELECT * FROM CategoryTree

我得到父类别的结果到底部，就像我得到计算机的所有子类别

但是我希望从动画到计算机的自下而上的结果，请一些人建议我正确的方向。

提前谢谢你：）

Answer 1

只需交换join子句中的字段：

WITH CategoryTree AS
        (
        SELECT  *, 0 AS Generation    
        FROM    dbo.Category
        WHERE   CategoryName = 'Animation'
        UNION ALL
        SELECT  Cat.*, Generation + 1    
        FROM    CategoryTree
        JOIN    dbo.Category AS Cat
        ON      Cat.Id = CategoryTree.CategoryMaster
        )
SELECT  *
FROM    CategoryTree

SQL递归查询

1 个答案: