SQL：嵌套SELECT在單個字段中具有多個值

Question

在我的SQL 2005數據庫中，我有一個表格，其值存儲爲與其他表格有關係的ID。因此，在我的MyDBO.warranty表中，我正在存儲product_id而不是product_name以節省空間。 product_name存儲在MyDBO.products。

當營銷部門拉動的人口統計資料，查詢相關表中的每個ID（下調爲簡潔起見），選擇相應的名稱：

SELECT w1.warranty_id AS "No.", 
     w1.created AS "Register Date" 
     w1.full_name AS "Name", 
     w1.purchase_date AS "Purchased", 
     (
      SELECT p1.product_name 
      FROM WarrDBO.products p1 WITH(NOLOCK) 
      WHERE p1.product_id = i1.product_id 
     ) AS "Product Purchased", 
     i1.accessories 
FROM WarrDBO.warranty w1 
LEFT OUTER JOIN WarrDBO.warranty_info i1 
    ON i1.warranty_id = w1.warranty_id 
ORDER BY w1.warranty_id ASC 

現在，我的問題是，「附件」列在warranty_info表存儲幾個值：

No.  Register Date Name    Purchased  Accessories 
--------------------------------------------------------------------- 
1500 1/1/2008   Smith, John  Some Product 5,7,9 
1501 1/1/2008   Hancock, John Another   2,3 
1502 1/1/2008   Brown, James  And Another  2,9 

我需要做同樣的事情與我與「產品」做「附件」，並從拉accessory_name MyDBO.accessories表使用accessory_id。我不知道從哪裏開始，因爲首先我需要提取ID，然後以某種方式將多個值連接成一個字符串。所以每行都會有「accessoryname1，accessoryname2，accessoryname3」：

No.  Register Date Name    Purchased  Accessories 
--------------------------------------------------------------------- 
1500 1/1/2008   Smith, John  Some Product Case,Bag,Padding 
1501 1/1/2008   Hancock, John Another   Wrap,Label 
1502 1/1/2008   Brown, James  And Another  Wrap,Padding 

我該怎麼做？

編輯>>發佈我的最終代碼：

我創造了這個功能：

CREATE FUNCTION SQL_GTOInc.Split 
(
    @delimited varchar(50), 
    @delimiter varchar(1) 
) RETURNS @t TABLE 
(
-- Id column can be commented out, not required for sql splitting string 
    id INT identity(1,1), -- I use this column for numbering splitted parts 
    val INT 
) 
AS 
BEGIN 
    declare @xml xml 
    set @xml = N'<root><r>' + replace(@delimited,@delimiter,'</r><r>') + '</r></root>' 

    insert into @t(val) 
    select 
    r.value('.','varchar(5)') as item 
    from @xml.nodes('//root/r') as records(r) 

    RETURN 
END 

並據此更新了我的代碼：

SELECT w1.warranty_id, 
     i1.accessories, 
     (
      CASE 
       WHEN i1.accessories <> '' AND i1.accessories <> 'NULL' AND LEN(i1.accessories) > 0 THEN 
        STUFF(
         (
          SELECT ', ' + a1.accessory 
          FROM MyDBO.accessories a1 
          INNER JOIN MyDBO.Split(i1.accessories, ',') a2 
          ON a1.accessory_id = a2.val 
          FOR XML PATH('') 
         ), 1, 1, '' 
        ) 
       ELSE '' 
      END 
     ) AS "Accessories" 
FROM MyDBO.warranty w1 
    LEFT OUTER JOIN MyDBO.warranty_info i1 
    ON i1.warranty_id = w1.warranty_id 

Answer 1

您可以編寫一個表值函數，它將逗號分隔的字符串拆分爲XML，並將XML節點轉換爲行。

參見： http://www.kodyaz.com/articles//t-sql-convert-split-delimeted-string-as-rows-using-xml.aspx

通過函數調用的結果加入到配飾，以及東西，結果回逗號分隔的名稱列表。

未經測試的代碼：

SELECT w1.warranty_id AS "No.", 
     w1.created AS "Register Date" 
     w1.full_name AS "Name", 
     w1.purchase_date AS "Purchased", 
     (
      SELECT p1.product_name 
      FROM WarrDBO.products p1 WITH(NOLOCK) 
      WHERE p1.product_id = i1.product_id 
     ) AS "Product Purchased", 
     STUFF(
     (
      SELECT 
      ', ' + a.name 
      FROM [table-valued-function](i1.accessories) acc_list 
      INNER JOIN accessories a ON acc_list.id = a.id 
      FOR XML PATH('') 
     ), 1, 1, '' 
     ) AS [accessories] 
FROM WarrDBO.warranty w1 
    LEFT OUTER JOIN WarrDBO.warranty_info i1 
    ON i1.warranty_id = w1.warranty_id 
ORDER BY w1.warranty_id ASC 

Answer 2

你只需要使用的功能FOR XML SQL Server輕鬆地掃描字符串：

來自鏈接的博客帖子：

SELECT 
    STUFF(
    (
    SELECT 
     ' ' + Description 
    FROM dbo.Brands 
    FOR XML PATH('') 
    ), 1, 1, '' 
) As concatenated_string 

要分析已經被存儲爲逗號分隔的你將不得不寫分析領域，並返回，然後可以用IN謂詞在WHERE中使用的表UDF場條款。看看here for starters和here。

Answer 3

無關，與你的問題。只是，你原來的查詢，也可以寫一個說明，subqery移動到一起，因爲：

SELECT w1.warranty_id AS "No.", 
     w1.created AS "Register Date" 
     w1.full_name AS "Name", 
     w1.purchase_date AS "Purchased", 
     p1.product_name AS "Product Purchased", 
     i1.accessories 
FROM WarrDBO.warranty w1 
INNER JOIN WarrDBO.products p1 
    ON p1.product_id = i1.product_id 
LEFT OUTER JOIN WarrDBO.warranty_info i1 
    ON i1.warranty_id = w1.warranty_id 
ORDER BY w1.warranty_id ASC 

Answer 4

這似乎是一個串連聚合函數工作。 在SQL它可以使用CLR

http://www.mssqltips.com/tip.asp?tip=2022