Question

我正在尝试从3个不同的表创建一些列的视图。其中一个列'OrderNumber'在2个表中，所以我试图为它们做一个UNION，但因为我做了一个子查询，它返回一个1242错误，并且不会返回超过1行。我只是想知道如何重写这个查询，以便没有子查询，或者有什么方法可以绕过它。或许我需要写多个查询？虽然我更愿意将其保留在一个查询中，谢谢。

CREATE VIEW CustOrderItems AS
SELECT CustFirstName,
       CustLastName,
       (SELECT OrderNumber
       FROM Orders
       UNION
       SELECT OrderNumber
       FROM Order_Details)
       OrderDate,
       ShipDate,
       QuantityOrdered * QuotedPrice as ItemTotal
FROM Customers JOIN Orders JOIN Order_Details;

Answer 1

目前尚不清楚你的连接标准是什么，因为语句语法不好。但我假设您想加入OrderNumber，例如SELECT ... FROM Customers INNER JOIN Orders ON Customers.OrderNumber = Orders.OrderNumber。在这种情况下，如果您想使用两个表中的订单号，只需重复查询并将两者结合起来，如： SELECT ,,, FROM Customers INNER JOIN Order_Details ON Customers.OrderNumber = Order_Details.OrderNumber 联盟从客户INNER JOIN订单中选择Customers.OrderNumber = Orders.OrderNumber

Answer 2

替换您的客户ID

drop view if exists custorders;
create view custorders as
SELECT     c.CustFirstName,
           c.CustLastName,
           o.OrderNumber order_ordernumber,
           od.OrderNumber orderdetails_ordernumber,
           o.OrderDate,
           o.ShipDate,
           od.QuantityOrdered * od.QuotedPrice as ItemTotal
FROM Customers c
JOIN Orders o on c.id = o.cust_id
JOIN Order_Details od on o.ordernumber = od.ordernumber
where c.id = ?

MySQL错误代码1242

2 个答案: