SQL检索树结构查询

Question

我有2个表

Products表：

ID  ProductName Category 
0  T-Shirt  15 
1  Aqua De Gio 12 
2  Jacket   15 
3  Hot Water  13 

Categories表：

categoryID catagoryName  highercategoryID 
8   Fragnance   0 
99   Clothing   0 
15   Armani Clothing 99 
12   Armani Fragnance 8 
102  Davidoff Fragnance 8 

预期结果

ID  ProductName Category CategoryTree 
0  T-Shirt  15  Clothing > Armani Cloting 
1  Aqua De Gio 12  Fragnance > Armani Fragnance 
2  Jacket   15  Clothing > Armani Cloting 
3  Hot Water  13  Fragnance > Davidoff Fragnance 

例如走T-S希尔特从产品表

1. 其类别为15
2. 去类别表，看看那里的categoryID = 15
3. 看看highercategoryID如果= 0停止，如果不是再取它的值99
4. 在categoryID列中寻找99，现在较高的类别是0，所以停下来。 根据以上我需要得到“服装>阿玛尼服装”。

我是新来的SQL查询，这里是我的第一次尝试

select 
    x.*, 
    x.p1 + isnull((' > ' + x.c1), '') + isnull((' > ' + x.c2), '') as CategoryTree 
from 
    (select 
     RP.categoryid as catid, 
     RP.catagoryName as p1, 
     R1.catagoryName as c1, 
     R2.catagoryName as c2 
    from 
     categories as RP 
    left outer join 
     categories as R1 on R1.highercategoryid = RP.categoryid 
    left outer join 
     categories as R2 on R2.highercategoryid = R1.categoryid 
    left outer join 
     categories as R3 on R3.highercategoryid = R2.categoryid 
    where 
     RP.highercategoryid != 0) x 

我不知道如何停止的加盟时，我发现在更高等级的0值，以及如何加入产品在他们的类别中，并且有没有使用大量联接的动态方式？

Answer 1

这里有云：

With CTE (CatID, CatName, HigherCatID) AS 
(
    SELECT categoryID, CAST(catagoryName AS VARCHAR(1000)), highercategoryID 
    FROM CATEGORIES 
    UNION ALL 
    SELECT C.categoryID, CAST(CTE.CatName + ' > ' + C.catagoryName AS VARCHAR(1000)), CTE.HigherCatID 
    FROM CATEGORIES C 
    INNER JOIN CTE ON C.HigherCategoryID = CTE.CatID 
) 
SELECT P.ID, P.ProductName, Cte.CatID, CTE.CatName 
FROM CTE INNER JOIN PRODUCTS P 
ON (CatID = P.Category) 
WHERE CTE.HigherCatID=0 

你有SQLFiddle Here