Question

我正在尝试从Northwind数据库中创建每个客户每年下的订单数量的视图。但是，我在Azure Data Studio上收到错误消息“选择列表中的列'Northwind.dbo.Orders.OrderDate'无效，因为它不包含在聚合函数或GROUP BY子句中”。我的代码在下面。

CREATE OR ALTER VIEW vCustomerOrderCounts AS 
SELECT 
  CompanyName,
  Count(OrderID) AS 'NumberOfOrders',
  Year(OrderDate) AS 'Order Year'
FROM Northwind.dbo.Customers, Northwind.dbo.Orders
GROUP BY CompanyName;
GO

SELECT * FROM vCustomerOrderCounts

Answer 1

从不在FROM子句中使用逗号。始终使用正确的，明确的，标准 JOIN语法。

您的GROUP BY和SELECT不兼容。另外，我强烈建议您使用不需要转义的列名：

CREATE OR ALTER VIEW vCustomerOrderCounts AS 
    SELECT c.CompanyName,
           Count(*) AS NumberOfOrders,
           Year(o.OrderDate) AS OrderYear
    FROM Northwind.dbo.Customers c JOIN
         Northwind.dbo.Orders o
         ON c.customerId = o.customerId -- or whatever the JOIN conditions are
    GROUP BY c.CompanyName, Year(o.OrderDate);

创建视图时出现问题，列无效

1 个答案: