SQL Calcluated字段轉換數據的行成基於列的多個值

Question

說我有一個看起來像這樣的數據線：

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

但我想改變一下這樣的數據：

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

這可能嗎？是否有計算出的邏輯可以使用頂級數據行爲產品和金額花費創建？

謝謝！

Answer 1

我想做到這一點使用cross apply：

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);