Question

我正在使用分层数据并使用递归CTE列出这样的项目：

Eletronics
    Televisions
        Tube
        LCD
        Plasma
    Portable Electronic
        MP3 Players
            Flash
        CD Player
        Two Way Radios

我的问题是：
如何按标题排序并尊重层次结构？

像这样：

Eletronics
    Portable Electronic
        CD Player
        MP3 Players
            Flash
        Two Way Radios
    Televisions
        LCD
        Plasma
        Tube

韩国社交协会

Answer 1

这是正确的CTE（仅适用于asc）

;WITH CTE AS
(
SELECT  id, id_parent, name_product
        ,HierarchicalPath = CAST('\'+CAST(name_product AS VARCHAR(MAX)) AS VARCHAR(MAX)) 
FROM @tab where id_parent is null -- Starts with the first level

UNION ALL

SELECT  t.id, t.id_parent, t.name_product
        ,HierarchicalPath = CAST(c.HierarchicalPath + '\'+CAST(t.name_product AS VARCHAR(MAX)) AS VARCHAR(MAX))
FROM @tab t INNER JOIN CTE C
ON t.id_parent = C.id
)

select * from cte order by HierarchicalPath

Answer 2

这是我几乎完成了我想要的代码。现在的问题是通过desc

订购

declare @tab table(
    id int identity(1,1)
    ,id_parent int
    ,name_product varchar(100)
)

insert into @tab
select null, 'Eletronics'
union all
select 1, 'Televisions'
union all
select 2, 'Tube'
union all
select 2, 'LCD'
union all
select 2, 'Plasma'
union all
select 1, 'Portable Electronic'
union all
select 6, 'MP3 Players'
union all
select 7, 'Flash'
union all
select 6, 'CD Player'
union all
select 6, 'Two Way Radios'

;WITH CTE (id,id_parent,name_product,LEVEL,SORTKEY)AS
(
    SELECT id, id_parent, name_product, 1, CAST(name_product AS VARBINARY(MAX))
    FROM @tab where id_parent is null -- Starts with the first level

    UNION ALL

    SELECT t.id, t.id_parent, t.name_product, C.LEVEL + 1, CAST(C.SORTKEY + CAST(t.name_product AS VARBINARY(MAX)) AS VARBINARY(MAX))
    FROM @tab t INNER JOIN CTE C
    ON t.id_parent = C.id
)

select * from cte order by SORTKEY

韩国社交协会

Answer 3

基于@onaiggac的变体（你可以使用他的数据:-)）

;WITH CTE (id, id_parent, name_product, LEVEL, SORTKEY) AS
(
    SELECT id, id_parent, name_product, 1, 
        CAST(ROW_NUMBER() OVER (ORDER BY name_product) AS VARBINARY(MAX))
    FROM @tab where id_parent is null -- Starts with the first level

    UNION ALL

    SELECT t.id, t.id_parent, t.name_product, C.LEVEL + 1, 
        C.SORTKEY + CAST(ROW_NUMBER() OVER (ORDER BY t.name_product) AS VARBINARY(MAX))
    FROM @tab t 
    INNER JOIN CTE C ON t.id_parent = C.id
)

SELECT id, id_parent, REPLICATE('   ', LEVEL - 1) + name_product, LEVEL, SORTKEY FROM CTE ORDER BY SORTKEY

这里的诀窍是使用

ROW_NUMBER() OVER (ORDER BY name_product)

做“内心”排序。与在@onaiggac中一样，它由二进制varbinary(max)

组成

CAST(ROW_NUMBER() OVER (ORDER BY name_product) AS VARBINARY(MAX))

然后以递归方式添加......

C.SORTKEY + CAST(ROW_NUMBER() OVER (ORDER BY t.name_product) AS VARBINARY(MAX))

请注意，ROW_NUMBER()会返回bigint ...您可以将其投放到int，然后再投放到VARBINARY(MAX)，例如

CAST(CAST(ROW_NUMBER() OVER (ORDER BY name_product) AS INT) AS VARBINARY(MAX))

如果你真的想...我认为除非你的树真的深，否则我认为没有必要。

递归CTE与订单

3 个答案: