Group By First Row

Question

SELECT OrderNumber, FIRST(ShippingName) as ShippingName FROM Orders 
GROUP BY OrderNumber 

這給出了一個錯誤，我該怎麼做？

Answer 1

SQL Server不支持FIRST函數。

也許你想

SELECT OrderNumber, MIN(ShippingName) as ShippingName 
FROM Orders 
GROUP BY OrderNumber 

但是，可能不會。相反，我懷疑你的意思是......對於每個OrderNumber，在所有具有該OrderNumber的行中，按照某種順序選擇第一行的ShippingName。

SELECT OrderNumber, 
    (
     SELECT TOP 1 ShippingName 
     FROM Orders AS OrdersInner 
     WHERE OrdersInner.OrderNumber = Orders.OrderNumber 
     ORDER BY OrdersInner.OrderDate, OrdersInner.OrderId 
    ) as ShippingName 
FROM Orders 
GROUP BY OrderNumber 

但我對你的需求和你的數據庫結構做了一些假設。

Answer 2

您也許意味着：

SELECT TOP 1 OrderNumber, ShippingName 
FROM Orders 
ORDER BY OrderNumber DESC