SqlServer 递归查询

表：

CREATE TABLE Category（

　　ID　　　　　　INT,

　　NAME 　　　　INT,

　　ParentID　　　INT

）

向上递归：

　

CREATE    FUNCTION [dbo].[GetRootCategoryID]
/*
    Author:yanghh
    Date:2009-08-10
    des:得到某一类根结点
*/
(
    @CategoryID INT
)
RETURNS @SubCategory TABLE(CategoryID INT,Level INT)
AS
BEGIN
    DECLARE @level    INT
    SET @level = 0
    INSERT INTO @SubCategory
    SELECT ID,@level FROM Category WHERE ID=@CategoryID
    WHILE @@ROWCOUNT >0
    BEGIN
        SET @level = @level+1
        INSERT INTO @SubCategory
        SELECT ParentId,@level FROM Category A, @SubCategory B 
            WHERE B.CategoryID = A.ID AND B.Level=@level-1
    END
    RETURN
END

向下递归：

CREATE    FUNCTION [dbo].[GetChildCategoryID]
/*
    Author:yanghh
    Date:2009-08-10
    des:得到某一类别子结点

*/
(
    @CategoryID INT
)
RETURNS @SubCategory TABLE(CategoryID INT,Level INT)
AS
BEGIN
    DECLARE @level    INT
    SET @level = 0
    INSERT INTO @SubCategory
    SELECT ID,@level FROM CC_VOD_FilmCategory WHERE ID=@CategoryID
    WHILE @@ROWCOUNT >0
    BEGIN
        SET @level = @level+1
        INSERT INTO @SubCategory
        SELECT ParentId,@level FROM Category A, @SubCategory B 
            WHERE B.CategoryID = A.ParentID AND B.Level=@level-1
    END
    RETURN
END