使用 SQL 服务器通过自连接转置 table

Question

我正在尝试找到正确的查询来动态转置 table/matrix 的第一行并将它们与其他值并排放置，

表 1:

ID   | System1 | System2 | System3 | System4 |
1    |         | Admin   | Lunch   | Training|
2    | INFO    | INFO    | INFO    | INFO    |
3    | INFO    | INFO    | INFO    | INFO    |
4    | IN      | IN      | IN      | IN      |

查询结果应如下：

ID   | System1 | System1_1| System2 | System2_2 | System3 | System3_3 | System4 | System4_4 | 
2    | INFO    |          | INFO    | Admin     | INFO    | Lunch     | INFO    | Training  | 
3    | INFO    |          | INFO    | Admin     | INFO    | Lunch     | INFO    | Training  |
4    | IN      |          | IN      | Admin     | IN      | Lunch     | IN      | Training  |

如您所见，我将顶行值转置到相关的新列中。这样，这些值并排属于同一条记录。

如何通过自连接实现此目的？

Answer 1

使用自联接，您可以：

select t.id, 
    t.system1, t1.system1 as system1_1, 
    t.system2, t1.system2 as system2_1, 
    t.system3, t1.system3 as system3_1,
    t.system4, t1.system4 as system4_1
from mytable t
cross join mytable t1
where t.id > 1 and t1.id = 1

使用 SQL 服务器通过自连接转置 table

Transposing a table by self-join using SQL Server

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