将行转换为列

Question

select ID, Vehicle from table

原始结果是

ID      Vehicle
--------------------
1       Car
1       Bike
1       Scooter
...
1       N.Product

我期望的结果

ID    Vehicle1   Vehicle2   Vehicle3  ....VehicleN
-----------------------------------------------------
1     Car         Bike       Scooter       N.Product

我浏览了与数据透视有关的示例，但它们没有帮助。有什么建议吗？

Answer 1

您可以使用row_number()进行透视或条件聚合：

select id,
       max(case when seqnum = 1 then vehicle end) as vehicle_1,
       max(case when seqnum = 2 then vehicle end) as vehicle_2,
       . . .
       max(case when seqnum = n then vehicle end) as vehicle_n
from (select t.*, 
             row_number() over (partition by id order by vehicle) as seqnum
      from t
     ) t
group by id;

这假定您知道结果集中所需的列数。如果不是这种情况，则需要使用动态SQL或将载具聚合为字符串。

Answer 2

我通过创建一个临时表然后使用while循环，添加列和更新值来做到这一点