Question

我想在northwind数据库中执行以下操作：

显示客户在CA中放置的所有产品的产品名称 但我很困惑如何将产品与客户联系起来。

Answer 1

根据我的回忆，您需要将products表加入orders，orderDetails和customers表，以获取客户订购的产品列表CA：

select distinct p.ProductName
from customers c
inner join orders o
  on c.customerId = o.customerId
inner join orderDetails od
  on o.orderId = od.orderid
inner join products p
  on od.productid = p.productid
where c.Region = 'CA'

或者您可以使用EXISTS：

select p.ProductName
from products p
where exists (select od.productid
              from customers c
              inner join orders o
                on c.customerId = o.customerId
              inner join orderDetails od
                on o.orderId = od.orderid 
              where c.Region = 'CA'
                and p.productid = od.productid)

请参阅两个查询的SQL Fiddle with Demo of sample。

Answer 2

试试这个：

Select o.pdt_name From orders o 
Where o.cust_no in 
 (Select c.cust_no From customers c Where c.state = 'CA')
order by o.pdt_name

Answer 3

以下为我完成了这份工作

Select distinct Products.ProductName From Products 
Where Products.ProductID in 
 (Select [Order Details].ProductID From [Order Details] Where [Order Details].OrderID in(select Orders.OrderID from Orders where Orders.CustomerID in(select Customers.CustomerID from Customers where Customers.Region='CA')))
 order by Products.ProductName;

Answer 4

SELECT DISTINCT PRD.PRODUCTNAME 
FROM CUSTOMERS AS CUST
INNER JOIN ORDERS AS ORD
ON CUST.CUSTOMERID=ORD.CUSTOMERID
INNER JOIN [ORDER DETAILS] AS ORDDETAILS
ON ORD.ORDERID=ORDDETAILS.ORDERID
INNER JOIN PRODUCTS AS PRD
ON ORDDETAILS.PRODUCTID=PRD.PRODUCTID
WHERE CUST.REGION='CA'

按产品名称按升序列出结果，将其添加到结尾

ORDER BY PRD.PRODUCTNAME ASC

选择北风产品的区域信息

4 个答案: