如何在LINQ中仅选择日期最高的记录 [英] How to select only the records with the highest date in LINQ

问题描述

我有一个表lasttraces"，其中包含以下字段.

I have a table, 'lasttraces', with the following fields.

Id, AccountId, Version, DownloadNo, Date

数据如下:

28092|15240000|1.0.7.1782|2009040004731|2009-01-20 13:10:22.000
28094|61615000|1.0.7.1782|2009040007696|2009-01-20 13:11:38.000
28095|95317000|1.0.7.1782|2009040007695|2009-01-20 13:10:18.000
28101|15240000|1.0.7.1782|2009040004740|2009-01-20 14:10:22.000
28103|61615000|1.0.7.1782|2009040007690|2009-01-20 14:11:38.000
28104|95317000|1.0.7.1782|2009040007710|2009-01-20 14:10:18.000

我如何才能在 LINQ to SQL 中只获取最后一条记录每个 AccountId(日期最高的那个)?

How can I, in LINQ to SQL, only get the last lasttrace of every AccountId (the one with the highest date)?

推荐答案

如果您只想要每个帐户的最后日期，您可以使用这个:

If you just want the last date for each account, you'd use this:

var q = from n in table
        group n by n.AccountId into g
        select new {AccountId = g.Key, Date = g.Max(t=>t.Date)};

如果你想要整个记录:

var q = from n in table
        group n by n.AccountId into g
        select g.OrderByDescending(t=>t.Date).FirstOrDefault();

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