SQL Server 选择最后 N 行 [英] SQL Server SELECT LAST N Rows

问题描述

这是一个已知问题，但我找到的最佳解决方案如下:

This is a known question but the best solution I've found is something like:

SELECT TOP N *
FROM MyTable
ORDER BY Id DESC

我有一张有很多行的表.使用该查询是不可能的，因为它需要很多时间.那么如何在不使用 ORDER BY 的情况下选择最后 N 行?

I've a table with lots of rows. It is not a posibility to use that query because it takes lot of time. So how can I do to select last N rows without using ORDER BY?

编辑

抱歉重复了这个问题一个

推荐答案

您也可以使用 ROW NUMBER BY PARTITION 功能来实现.一个很好的例子可以在这里找到:

You can do it by using the ROW NUMBER BY PARTITION Feature also. A great example can be found here:

我正在使用 Northwind 数据库的 Orders 表...现在让我们检索员工 5 下的最后 5 个订单:

I am using the Orders table of the Northwind database... Now let us retrieve the Last 5 orders placed by Employee 5:

SELECT ORDERID, CUSTOMERID, OrderDate
FROM
(
    SELECT ROW_NUMBER() OVER (PARTITION BY EmployeeID ORDER BY OrderDate DESC) AS OrderedDate,*
    FROM Orders
) as ordlist

WHERE ordlist.EmployeeID = 5
AND ordlist.OrderedDate <= 5

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