在Sybase SQL查询中进行透视？

Question

我正在寻找一种方法来调整以下结果......

ID | Group_Level | Group_Values
1  | Division    | Value 1 
2  | Department  | Value 2
3  | Class       | Value 3

进入以下结构....

ID | Division | Department | Class
1  | Value 1  | Value 2    | Value 3    
2  | Value 1  | Value 2    | Value 3

列数是固定的(它将始终为division/department/class).该查询适用于Sybase ...已经无法弄清楚如何实现这种旋转.有什么建议？

Answer 1

转向固定数量列的经典方法如下:

select id,
max (case when group_level = 'Division' then Group_Values else null end) Division,
max (case when group_level = 'Department' then Group_Values else null end) Department,
max (case when group_level = 'Class' then Group_Values else null end) Class
from
YourTable
group by id

Answer 2

您需要一些键来定义 3 行集。然后，您只需自行加入

所以对于这样的数据...

ID | GroupID | Group_Level | Group_Values
1  | 1 | Division    | Value 1
2  | 1 | Department  | Value 2
3  | 1 | Class       | Value 3
4  | 2 | Division    | Value 1
5  | 2 | Department  | Value 2
6  | 2 | Class       | Value 3

你会有

SELECT
   Div.GroupID, Div.Group_Values, Dept.Group_Values, Cl.Group_Values
FROM
   MyTable Div
   JOIN
   MyTable Dept ON Div.GroupID = Dept.GroupID
   JOIN
   MyTable Cl ON Div.GroupID = Cl.GroupID
WHERE
   Div.Group_Level = 'Division'
   AND
   Dept.Group_Level = 'Department'
   AND
   Cl.Group_Level = 'Class'