这种转置如何写

请教大家这种转置怎么写？
客户字段A字段B字段C
A102030
B405060
B708090


客户字段类型值
A字段A10
A字段B20
A字段C30
B字段A40
B字段B50
B字段C60
B字段A70
B字段B80
B字段C90

谢谢指点。

[解决办法]

SQL code

select 客户,'字段A' as 字段类型,字段A as 值 from tbunion allselect 客户,'字段B' as 字段类型,字段B as 值 from tbunion allselect 客户,'字段C' as 字段类型,字段C as 值 from tb
[解决办法]
SQL code
declare @T table([客户] varchar(1),[字段A] int,[字段B] int,[字段C] int)insert @Tselect 'A',10,20,30 union allselect 'B',40,50,60 union allselect 'B',70,80,90select [客户],'[字段A]' as 字段类型,[字段A] as 值 from @T union allselect [客户],'[字段B]' as 字段类型,[字段B]  from @T union allselect [客户],'[字段C]' as 字段类型,[字段C]  from @T order by 1,3/*客户   字段类型    值---- ------- -----------A    [字段A]   10A    [字段B]   20A    [字段C]   30B    [字段A]   40B    [字段B]   50B    [字段C]   60B    [字段A]   70B    [字段B]   80B    [字段C]   90*/