客户未订购的产品列表？

Question

我在这里遇到了一个问题。我需要查看客户 X 没有购买的产品。即，“Jane D”（客户）尚未订购哪些产品。下面是数据库设计。在编码时，我最终得到了该客户订购的产品，但无法获得他/她没有订购的产品。你能帮忙吗？

我想要的是库存中的产品列表，客户还没有订购。不是产品表中的那个

Customer: customer_id, customer_name

Order: order_id, customer_id,inventory_id, order_Date

Inventory: Inventory_id, product_ID

Product: product_id, product_name

from below query i can find what customer_id=1 has bought


SELECT p.Product_ID, p.Product_NAME
FROM CUSTOMER C JOIN Order O ON c.customer_id=o.customer_id
JOIN INVENTORY I ON o.inventory_id=i.inventory_id
JOIN product p ON i.product_id=p.product_id
WHERE C.CUSTOMER_ID='1';

Answer 1

SELECT p.Product_ID, p.Product_NAME
FROM product p 
JOIN INVENTORY i ON p.product_id = i.product_id
LEFT JOIN Order o
        ON o.inventory_id = i.inventory_id
        AND o.customer_id = '1'
WHERE o.customer_id IS NULL

Answer 2

以下查询将给出所需的结果。右外连接和空检查可以为您解决问题。

SELECT p.Product_ID, p.Product_NAME
FROM CUSTOMER C JOIN Order O ON c.customer_id=o.customer_id
JOIN INVENTORY I ON o.inventory_id=i.inventory_id
RIGHT OUTER JOIN product p ON i.product_id_id=p.product_id
WHERE C.CUSTOMER_ID='1' and i.product_id is null;