sql - 按第一行分组

Question

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

这给出了一个错误，我该怎么做？

Answer 1

FIRSTSQL Server 不支持该函数。

也许你想要

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

但是，可能不会。相反，我怀疑您的意思是...对于每个OrderNumber, 在所有带有 that 的行中，根据某些顺序OrderNumber选择第一行的 。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

但我正在对您的要求和数据库结构做出一些假设。

Answer 2

你可能的意思是：

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