sql - 根据 ID 列将行转置为列

Question

我目前正在运行 SQL Server 2008 并尝试获取以下子查询数据：

ID | Field Name | Field Selection
1  |  Rating 1  |      Good
1  |  Rating 2  |      Good
1  |  Rating 3  |      Bad
2  |  Rating 1  |      OK

根据 ID 列分组为一行：

ID | Rating 1 | Rating 2 | Rating 3
1  |    Good  |    Good  |   Bad
2  |     OK   |    NULL  |   NULL

这可能吗？提前致谢！

干杯，西

Answer 1

您可以为此使用 SQL Server 数据透视子句：

select
    p.*
from Table1
pivot(
    max([Field Selection])
    for [Field Name] in ([Rating 1], [Rating 2], [Rating 3])
) as p

或者您可以手动旋转：

select
    ID,
    max(case when [Field Name] = 'Rating 1' then [Field Selection] end) as [Rating 1], 
    max(case when [Field Name] = 'Rating 2' then [Field Selection] end) as [Rating 2],
    max(case when [Field Name] = 'Rating 3' then [Field Selection] end) as [Rating 3]
from Table1
group by ID

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