SQL 将列转换为行答案

【问题标题】：SQL Convert Columns into RowsSQL 将列转换为行
【发布时间】：2014-04-08 10:17:49
【问题描述】：

我有一个三列 18 行的表格。我想改成两行的 18 列。这是表格

类别乐队积分 20_CAT1 21-22 10 20_CAT2 23-25 20 20_CAT3 26- 30 30_CAT1 31-33 10 30_CAT2 34-38 20 30_CAT3 39- 30 40_CAT1 41-44 5 40_CAT2 45-50 15 40_CAT3 51- 25 50_CAT1 50-55 5 50_CAT2 56-63 15 50_CAT3 64- 25 60_CAT1 61-66 5 60_CAT2 67-75 20 60_CAT3 76- 30 70_CAT1 71-77 5 70_CAT2 78-88 20 70_CAT3 89- 30

新表应以“类别”为列，以“带”和“点”为行

我不确定如何使用 Cross Apply 和 Pivot 来执行此操作，或者即使这是正确的方法。

提前致谢。

【问题讨论】：

看起来同时拥有 Category 和 Bands 列是多余的，因为它们具有一对一的映射关系。
How to pivot unknown number of columns & no aggregate in SQL Server? 的可能重复项
感谢 M Ali，我正在为您示例中的语法以及如何将其应用于我的问题而苦苦挣扎。任何进一步的帮助将不胜感激。

标签： sql-server sql-server-2008-r2 pivot cross-apply

【解决方案1】：

我已经设法在不使用 PIVOT 的情况下完成以下工作。

        SELECT
        MAX(CASE WHEN Category = '20_CAT1' THEN Bands END) [20_CAT1_Bands],
        MAX(CASE WHEN Category = '20_CAT1' THEN Points END) [20_CAT1_Points],
        MAX(CASE WHEN Category = '20_CAT2' THEN Bands END) [20_CAT2_Bands],
        MAX(CASE WHEN Category = '20_CAT2' THEN Points END) [20_CAT2_Points],
        MAX(CASE WHEN Category = '20_CAT3' THEN Bands END) [20_CAT3_Bands],
        MAX(CASE WHEN Category = '20_CAT3' THEN Points END) [20_CAT3_Points],

        MAX(CASE WHEN Category = '30_CAT1' THEN Bands END) [30_CAT1_Bands],
        MAX(CASE WHEN Category = '30_CAT1' THEN Points END) [30_CAT1_Points],
        MAX(CASE WHEN Category = '30_CAT2' THEN Bands END) [30_CAT2_Bands],
        MAX(CASE WHEN Category = '30_CAT2' THEN Points END) [30_CAT2_Points],
        MAX(CASE WHEN Category = '30_CAT3' THEN Bands END) [30_CAT3_Bands],
        MAX(CASE WHEN Category = '30_CAT3' THEN Points END) [30_CAT3_Points],

        MAX(CASE WHEN Category = '40_CAT1' THEN Bands END) [40_CAT1_Bands],
        MAX(CASE WHEN Category = '40_CAT1' THEN Points END) [40_CAT1_Points],
        MAX(CASE WHEN Category = '40_CAT2' THEN Bands END) [40_CAT2_Bands],
        MAX(CASE WHEN Category = '40_CAT2' THEN Points END) [40_CAT2_Points],
        MAX(CASE WHEN Category = '40_CAT3' THEN Bands END) [40_CAT3_Bands],
        MAX(CASE WHEN Category = '40_CAT3' THEN Points END) [40_CAT3_Points],

        MAX(CASE WHEN Category = '50_CAT1' THEN Bands END) [50_CAT1_Bands],
        MAX(CASE WHEN Category = '50_CAT1' THEN Points END) [50_CAT1_Points],
        MAX(CASE WHEN Category = '50_CAT2' THEN Bands END) [50_CAT2_Bands],
        MAX(CASE WHEN Category = '50_CAT2' THEN Points END) [50_CAT2_Points],
        MAX(CASE WHEN Category = '50_CAT3' THEN Bands END) [50_CAT3_Bands],
        MAX(CASE WHEN Category = '50_CAT3' THEN Points END) [50_CAT3_Points],

        MAX(CASE WHEN Category = '60_CAT1' THEN Bands END) [60_CAT1_Bands],
        MAX(CASE WHEN Category = '60_CAT1' THEN Points END) [60_CAT1_Points],
        MAX(CASE WHEN Category = '60_CAT2' THEN Bands END) [60_CAT2_Bands],
        MAX(CASE WHEN Category = '60_CAT2' THEN Points END) [60_CAT2_Points],
        MAX(CASE WHEN Category = '60_CAT3' THEN Bands END) [60_CAT3_Bands],
        MAX(CASE WHEN Category = '60_CAT3' THEN Points END) [60_CAT3_Points],

        MAX(CASE WHEN Category = '70_CAT1' THEN Bands END) [70_CAT1_Bands],
        MAX(CASE WHEN Category = '70_CAT1' THEN Points END) [70_CAT1_Points],
        MAX(CASE WHEN Category = '70_CAT2' THEN Bands END) [70_CAT2_Bands],
        MAX(CASE WHEN Category = '70_CAT2' THEN Points END) [70_CAT2_Points],
        MAX(CASE WHEN Category = '70_CAT3' THEN Bands END) [70_CAT3_Bands],
        MAX(CASE WHEN Category = '70_CAT3' THEN Points END) [70_CAT3_Points]

    FROM @table

【讨论】：

当您想要调整两个度量时，这几乎是唯一的解决方案。