SQL查詢問題

Question

我有一個場景，我需要將行轉換爲列。我可能需要使用PIVOT，但我無法弄清楚這一點。

這裏是什麼，我有一個簡化版： 表：ContentAuthor

ContentID | AuthorName 
---------------------- 
1   | Joe 
1   | John 
1   | Mary 
2   | John 
2   | Dan 
3   | Sam 

我想獲得：

ContentID | Author1 | Author2 | Author3 | Author4 | Author5 
----------------------------------------------------------------- 
1   | Joe  | John  | Mary  |   | 
2   | John  | Dan  |   |   | 
3   | Sam  |   |   |   | 

在這一點上我真的不關心爲了它們出現。

任何幫助將不勝感激。

Answer 1

這將每ContentId高達5名作者的工作，如果你需要允許任意金額，那麼你將需要使用dynamic SQL

;WITH ContentAuthor(ContentID, AuthorName) AS 
(
SELECT 1,'Joe' UNION ALL 
SELECT 1,'John' UNION ALL 
SELECT 1,'Mary' UNION ALL 
SELECT 2,'John' UNION ALL 
SELECT 2,'Dan' UNION ALL 
SELECT 3,'Sam' 
),T AS 
(
SELECT *, 
     ROW_NUMBER() OVER (PARTITION BY ContentID ORDER BY (SELECT 0)) RN 
FROM ContentAuthor 
) 
SELECT ContentID, 
     [1] AS Author1, 
     [2] AS Author2, 
     [3] AS Author3, 
     [4] AS Author4, 
     [5] AS Author5 
FROM T 
PIVOT(MAX(AuthorName) FOR RN IN ([1],[2],[3],[4],[5])) AS Pvt;