将行转换为列SQL Server 2005/8

我刚刚开始深入了解SQL Server，我遇到了一个问题。我必须把一行转换成一列，但我想不出来

该行如下所示：

   Columns:      T1 T2 T3 .........T20
    Values:      1   0  9 ......... 15

    Col  Val
    ________
    T1    1
    T2    0
    T3    9
    ........
    T20   15

SELECT col, val
FROM Tablename AS t
UNPIVOT
(
   Val
   FOR Col IN (T1, T2, ..., T20)
) AS u;

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' +
                        QUOTENAME(column_name)
                      FROM information_schema.columns
                      WHERE table_name = 'tablename'
                      FOR XML PATH(''), TYPE
                     ).value('.', 'NVARCHAR(MAX)') 
                        , 1, 1, '');

SELECT @query = ' SELECT col, val
                  FROM tablename AS t
                  UNPIVOT
                  (
                  val
                  FOR col IN ( ' + @cols + ' )
                  ) AS u;';

EXECUTE(@query);

我想收到这样的东西：

   Columns:      T1 T2 T3 .........T20
    Values:      1   0  9 ......... 15

    Col  Val
    ________
    T1    1
    T2    0
    T3    9
    ........
    T20   15

SELECT col, val
FROM Tablename AS t
UNPIVOT
(
   Val
   FOR Col IN (T1, T2, ..., T20)
) AS u;

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' +
                        QUOTENAME(column_name)
                      FROM information_schema.columns
                      WHERE table_name = 'tablename'
                      FOR XML PATH(''), TYPE
                     ).value('.', 'NVARCHAR(MAX)') 
                        , 1, 1, '');

SELECT @query = ' SELECT col, val
                  FROM tablename AS t
                  UNPIVOT
                  (
                  val
                  FOR col IN ( ' + @cols + ' )
                  ) AS u;';

EXECUTE(@query);

我知道我必须使用枢轴，我已经读过这方面的内容，但我想不出它是什么

您必须使用表运算符来实现这一点，如下所示：

   Columns:      T1 T2 T3 .........T20
    Values:      1   0  9 ......... 15

    Col  Val
    ________
    T1    1
    T2    0
    T3    9
    ........
    T20   15

SELECT col, val
FROM Tablename AS t
UNPIVOT
(
   Val
   FOR Col IN (T1, T2, ..., T20)
) AS u;

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' +
                        QUOTENAME(column_name)
                      FROM information_schema.columns
                      WHERE table_name = 'tablename'
                      FOR XML PATH(''), TYPE
                     ).value('.', 'NVARCHAR(MAX)') 
                        , 1, 1, '');

SELECT @query = ' SELECT col, val
                  FROM tablename AS t
                  UNPIVOT
                  (
                  val
                  FOR col IN ( ' + @cols + ' )
                  ) AS u;';

EXECUTE(@query);

---

更新1 如果您想对任意数量的列动态执行此操作，而不需要手动写入，我唯一能想到的方法是从表

信息\u schema.columns

中读取这些列，以获取表的列名称列表。然后使用动态SQL动态地为col IN…编写语句，如下所示：

   Columns:      T1 T2 T3 .........T20
    Values:      1   0  9 ......... 15

    Col  Val
    ________
    T1    1
    T2    0
    T3    9
    ........
    T20   15

SELECT col, val
FROM Tablename AS t
UNPIVOT
(
   Val
   FOR Col IN (T1, T2, ..., T20)
) AS u;

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' +
                        QUOTENAME(column_name)
                      FROM information_schema.columns
                      WHERE table_name = 'tablename'
                      FOR XML PATH(''), TYPE
                     ).value('.', 'NVARCHAR(MAX)') 
                        , 1, 1, '');

SELECT @query = ' SELECT col, val
                  FROM tablename AS t
                  UNPIVOT
                  (
                  val
                  FOR col IN ( ' + @cols + ' )
                  ) AS u;';

EXECUTE(@query);

这将为您提供：

| COL | VAL |
-------------
|  T1 |   1 |
| T10 |  15 |
| T11 |  33 |
| T12 |  31 |
| T13 |  12 |
| T14 |  10 |
| T15 |  12 |
| T16 |   9 |
| T17 |  10 |
| T18 |   2 |
| T19 |  40 |
|  T2 |   0 |
| T20 |  21 |
|  T3 |   9 |
|  T4 |   2 |
|  T5 |   3 |
|  T6 |  10 |
|  T7 |  14 |
|  T8 |  15 |
|  T9 |  20 |

---

谢谢马哈茂德·贾马尔。工作起来很有魅力，我有一个开始：）人们必须事先知道要旋转的柱子。我有一个使用临时表和动态查询“发现”它们的解决方案，今天晚些时候我会发布（当我有时间这样做的时候）。我已经给了你+1，但我很高兴你也发布了一个动态版本。：）@蓝脚-谢谢。你是老板：）我刚从你那里学到了所有这些pivot/unpivot的东西。