每隔一列转置或取消旋转 [英] Transpose or unpivot every other column

问题描述

基本上我想要做的是将每隔一列转置为一行，旁边有以下列数据.

Basically what I am trying to do is transpose every other column to a row with the following columns data beside it.

源可以只有两列，最多一千和几百万行.我只是在每行的基础上这样做.我曾尝试执行UNION ALL"，但是在处理大表中的数百列时，这非常慢.

The source can have only two columns up to one-thousand and millions of rows. I am only doing this on a per-row basis. I have tried doing a "UNION ALL" however this is incredibly slow when dealing with hundreds of columns in a large table.

可能的解决方案是使用 UNPIVOT，尽管我能找到的每个示例都在做与我想要的不同的事情.

Possible solutions are using UNPIVOT although every example I can find is doing something different from what I want.

示例:查询前

Columns...
Apple | Apple Data | Banana | Banana  Data | Cranberry | Cranberry  Data | .... 

Data Returned... 
IOWA_PL_RLA | 1 | IOWA_PL_MATH | 1 | IOWA_SS_RLA 684 .....

示例:查询后

MeasureID  Score
CRCT_PL_RLA   | 1 
CRCT_PL_MATH  | 1 
CRCT_SS_RLA   |684 
.....

希望我已经对自己进行了足够的解释，以便有人可以提供帮助，因为我在 T-SQL 方面经验有限.如果需要更多信息，请告诉我.

Hopefully I have explained myself enough that someone can help as I am only moderately experienced in T-SQL. If more information is needed please let me know.

推荐答案

如果您使用的是 SQL Server 2008，我认为您应该考虑使用 CROSS APPLY (VALUES) 技术:

If you are using SQL Server 2008, I think you should look into using the CROSS APPLY (VALUES) technique:

http://www.sqlservercentral.com/articles/CROSS+APPLY+VALUES+UNPIVOT/91234/

基本上是这样的:

SELECT
  x.NewColumn1,
  x.NewColumn2
FROM YourTable t
CROSS APPLY (
    VALUES
        (t.OldColumn1, t.OldColumn2),
        (t.OldColumn3, t.OldColumn4),
        ...
) x (NewColumn1, NewColumn2);

这是一个可运行的示例:http://sqlfiddle.com/#!3/9a9d2/5/0

Here's a runnable example: http://sqlfiddle.com/#!3/9a9d2/5/0

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