SQL - 从另一个查询中为每一行复制多行

Question

我似乎有一个相对简单的任务要做，但是我的 SQL 知识有限，我的 google fu 对我来说失败了。尽管我可以通过编写 powershell 脚本或使用 notepad++ 来解决它，但我对如何使用 SQL 实现这一点非常感兴趣，特别是如果表变得非常大并且解决方法不是很可行没有了。

简单来说，我有两张表：

价格

Productname	Customer_ID	price1	price2	price3	price4
A	1	10	11	12	13
B	1	99	100	101	102
C	1	48	49	50	51
D	1	2	3	4	5
E	1	89	90	91	92

客户

Name	ID	Customer_Group
B	2	ABC
C	3	ABC
D	4	ABC
E	5	ABC
F	6	ABC

现在我想将 Customer_ID = 1 的价格表中的 5 行复制（即插入）回 Customer_Group = ABC 的客户表中每个客户的价格表。每次复制这5行时，我还需要将字段Customer_ID设置为customers表查询返回的ID。

所以价格表如下所示：

Productname	Customer_ID	price1	price2	price3	price4
A	1	10	11	12	13
B	1	99	100	101	102
C	1	48	49	50	51
D	1	2	3	4	5
E	1	89	90	91	92
A	2	10	11	12	13
B	2	99	100	101	102
C	2	48	49	50	51
D	2	2	3	4	5
E	2	89	90	91	92
A	3	10	11	12	13
B	3	99	100	101	102
C	3	48	49	50	51
D	3	2	3	4	5
E	3	89	90	91	92

（等等）

Answer 1

 SELECT *
 FROM CUSTOMERS            
 WHERE CUSTOMERS.NAME IN ('B','C','D','E','F') 
       -- may not be needed if you want all rows from customers table.

将选择您想要合作的所有客户

现在我们只需加入另一个表以获取数据

 SELECT *
 FROM CUSTOMERS
 JOIN PRICES ON  PRICES.Customer_ID = 1
 WHERE CUSTOMERS.Customer_Group = 'ABC'

选择您需要的列

 SELECT PRICES.ProductName, 
        CUSTOMERS.CustomerID,
        PRICES.price1, PRICES.price2, PRICES.price3, PRICES.price4
 FROM CUSTOMERS
 JOIN PRICES ON  PRICES.Customer_ID = 1
 WHERE CUSTOMERS.Customer_Group = 'ABC'

如果你想将它插入到表中，请在开头添加插入语句

 INSERT INTO PRICES 
      (Productname, Customer_ID, price1, price2, price3, price4, price5)
   SELECT PRICES.ProductName, 
          CUSTOMERS.CustomerID,
          PRICES.price1, PRICES.price2, PRICES.price3, PRICES.price4
   FROM CUSTOMERS
   JOIN PRICES ON  PRICES.Customer_ID = 1
   WHERE CUSTOMERS.Customer_Group = 'ABC'

Answer 2

总之，这是？

SELECT P.ProductName,
       P.Customer_ID,
       P.price1,
       P.price2, --This is a denormalised design, and you should fix this
       P.price3, --This is a denormalised design, and you should fix this
       P.price4 --This is a denormalised design, and you should fix this
FROM dbo.Prices P
--WHERE P.Customer = 1 --?
UNION ALL
SELECT P.ProductName,
       C.ID AS CustomerID,
       P.price1,
       P.price2, --This is a denormalised design, and you should fix this
       P.price3, --This is a denormalised design, and you should fix this
       P.price4 --This is a denormalised design, and you should fix this
FROM dbo.Prices P
     CROSS JOIN dbo.Customers C;
--WHERE P.Customer = 1 --?