sql – 复制父级和子级属性

2019年7月28日 213次阅读

我在解决克服其他公司的父/子产品类别的最合理方法时遇到了问题.

可以有3个级别的类别.

即.男士服装(L1)>衬衫(L2)>短袖(L3)(衬衫是短袖的母版,男士服装是衬衫的父母)

ParentCategoryIdis直接在上面的类别的ID.
ParentString是上面所有类别的Id,按级别排序.

(即对于L3产品,它将是L1的Id然后是L2的Id)
 表格设置如下.

CREATE TABLE #Categories
(
CategoryId INT
,CompanyId INT
,ParentCategoryId INT
,CategoryName VARCHAR(255)
,ParentString VARCHAR(20)
)
INSERT INTO #Categories VALUES
(123, 12, NULL, 'Mens Clothing',     NULL),
(124, 12, 123,  'Shirt',            '123-'),
(125, 12, NULL, 'Womens Clothing',  NULL),
(126, 12, 125,  'Shirt',            '125-'),
(127, 12, 124,  'Short Sleeve',     '123-124-'),
(128, 12, NULL, 'Drinks',           NULL),
(129, 12, 128,  'Water',            '128-')

我需要将所有类别和级别复制到CompanyId 13.

最佳答案 这是一个奇怪的解决方案.

>我们从公司12提供CTE所有东西,
>我们从此表中找到MAX id,然后将其添加到ROW_NUMBER(),
>将ParentString转换为XML,
>选择我们需要的,

并获得可插入Categories表中的输出(见下文)：

DECLARE @id int 

SELECT @id = MAX(CategoryId) FROM #Categories

;WITH cte AS (
SELECT  ROW_NUMBER() OVER (PARTITION BY CompanyId ORDER BY CategoryId) + @id as NewCategoryId,
        CategoryId as OldCategoryId,
        CompanyId,
        ParentCategoryId,
        CategoryName,
        CAST('<p>'+REPLACE(STUFF(ParentString,LEN(ParentString),1,''),'-','</p><p>')+'</p>' as xml) parentxml
FROM #Categories
WHERE CompanyId = 12
)

SELECT  c.NewCategoryId,
        13 as CompanyId,
        c1.NewCategoryId as NewParentCategoryId,
        c.CategoryName,
        (
        SELECT CAST(f.NewCategoryId as nvarchar(max)) +'-'
        FROM cte f
        OUTER APPLY (
            SELECT  t.c.value('.','int') as xpart
            FROM c.parentxml.nodes('/p') as t(c)
        ) x
        WHERE OldCategoryId = x.xpart
        FOR XML PATH('')
        ) as ParentString
FROM cte c
LEFT JOIN cte c1 
    ON c1.OldCategoryId = c.ParentCategoryId

输出：

NewCategoryId   CompanyId   NewParentCategoryId CategoryName    ParentString
130             13          NULL                Mens Clothing   NULL
131             13          130                 Shirt           130-
132             13          NULL                Womens Clothing NULL
133             13          132                 Shirt           132-
134             13          131                 Short Sleeve    130-131-
135             13          NULL                Drinks          NULL
136             13          135                 Water           135-

编辑

如果CategoryId列是自动递增的IDENTITY列,那么最好使用事务并打开IDENTITY_INSERT：

SET IDENTITY_INSERT Categories ON
BEGIN TRANSACTION
...
COMMIT TRANSACTION
SET IDENTITY_INSERT Categories OFf
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