将一组行转置为多列

Question

我正在尝试将一组行转换为多列。

到目前为止，我已经能够使用 for xml 路径将一组行聚合到一个列中，但我需要将更多数据保存到更多列中。

CntTyp 表（联系人类型）

| ContactID | CatCode | CatDesc |
|-----------|---------|---------|
| 89        | 26      | OA      |
| 89        | 27      | OA2     |
| 90        | 26      | OA      |
| 91        | 26      | OA      |
| 91        | 1625    | Donor   |
| 91        | 1625    | Player  |

期望的输出

| ContactID | CatCode | CatDesc | CatCode | CatDesc | CatCode | CatDesc |
|-----------|---------|---------|---------|---------|---------|---------|
| 89        | 26      | OA      | 27      | OA2     |         |         |
| 90        | 26      | OA      |         |         |         |         |
| 91        | 26      | OA      | 1625    | Donor   | 234     | Player  |

我的代码：

select ContactID, catInfo = 
STUFF((select ','+cast(t1.CatCode as varchar) 
from CntTyp t1  where t.ContactID = t1.ContactID  
for xml path ('')), 1, 1, '')
from CntTyp t 
group by ContactID

我的输出

| ContactID | catInfo     |
|-----------|-------------|
| 89        | 26,27       |
| 90        | 26          |
| 91        | 26,1625,234 |

Answer 1

我们可以尝试在ROW_NUMBER 的帮助下进行数据透视查询：

WITH cte AS (
    SELECT *,
        ROW_NUMBER() OVER (PARTITION BY ContactID ORDER BY CatCode, CatDesc) rn
    FROM CntTyp
)

SELECT
    ContactID,
    MAX(CASE WHEN rn = 1 THEN CatCode END) AS CatCode1,
    MAX(CASE WHEN rn = 1 THEN CatDesc END) AS CatDesc1,
    MAX(CASE WHEN rn = 2 THEN CatCode END) AS CatCode2,
    MAX(CASE WHEN rn = 2 THEN CatDesc END) AS CatDesc2,
    MAX(CASE WHEN rn = 3 THEN CatCode END) AS CatCode3,
    MAX(CASE WHEN rn = 3 THEN CatDesc END) AS CatDesc3
FROM cte
GROUP BY
    ContactID;