SQL Calcluated字段根据列值将数据行转换为多行

Question

说我的数据行看起来像这样：

[Customer] - [$ spent of shirts] - [$ spent on pants] - [$ spent on shoes]
John - $10 - $20 - $15   
Maria - $20 - $10 - $50 

但我想将数据转换为如下所示：

[Customer] - [Product] - [Amount Spent] 
John - Shirts - $10 
John - Pants - $20 
John - Shoes - $15
Maria - Shirts - $20
Maria - Pants - $10
Maria - Shoes - $50 

这可能吗？我是否可以使用顶部数据线为Product和Amount Spent创建计算逻辑？

谢谢！

Answer 1

我喜欢使用cross apply执行此操作：

select v.*
from t cross apply
     (values ([Customer], 'Shirts', [$ spent of shirts]),
             ([Customer], 'Pants', [$ spent of pants]),
             ([Customer], 'Shoes', [$ spent of shoes])
     ) v(Customer, Product, AmountSpent);