sql - 如何使用列中的可变数据透视表

Question

全部，

rownum  respnum   q2        q3
-----------------------------------
1       33        Missy     155-4
2       46        Melissa   55-98
3       73        Emma      998-4

您将如何旋转上表以在下面显示所需的结果？请记住，原始列标题是静态的（q2、q3、...），但答案可能会有所不同。

 rownum respnum   question  answer
-----------------------------------
1       33        q2        Missy
1       33        q3        155-4
2       46        q2        Melissa 
2       46        q3        55-98
3       73        q2        Emmat
3       73        q3        998-4

谢谢

Answer 1

UnPivot的性能会更高，但如果您不想指定所有字段，请考虑以下事项：

例子

Select rownum
      ,respnum
      ,C.*
 From YourTable A
 Cross Apply ( values (cast((Select A.* for XML RAW) as xml))) B(XMLData)
 Cross Apply (
                Select question = a.value('local-name(.)','varchar(100)')
                      ,answer   = a.value('.','varchar(max)') 
                 From  B.XMLData.nodes('/row')  as C1(n)
                 Cross Apply C1.n.nodes('./@*') as C2(a)
                 Where a.value('local-name(.)','varchar(100)') not in ('rownum','respnum')
             ) C

退货

rownum  respnum question    answer
1       33      q2          Missy
1       33      q3          155-4
2       46      q2          Melissa
2       46      q3          55-98
3       73      q2          Emma
3       73      q3          998-4

Answer 2

使用UNPIVOT，我们可以这样做：

select * from 
(select 
    rownum, 
    respnum, 
    Q2=Cast(q2 as varchar(max)),
    Q3=cast(Q3 as varchar (max)) 
 from sample)src
unpivot
( answer for question in ([q2],[q3]))up

see working demo