实体框架选择每个组的一个日期 [英] Entity Framework select one of each group by date

问题描述

我有这样的（表名：帖子）：表

I have a table like this (Table name: Posts):

+----+--------------------------+-------+------------+
| id |         content          | type  |    date    |
+----+--------------------------+-------+------------+
|  0 | Some text                | TypeA | 2013-04-01 |
|  1 | Some older text          | TypeA | 2012-03-01 |
|  2 | Some even older texttext | TypeA | 2011-01-01 |
|  3 | A dog                    | TypeB | 2013-04-01 |
|  4 | And older dog            | TypeB | 2012-03-01 |
|  5 | An even older dog        | TypeB | 2011-01-01 |
+----+--------------------------+-------+------------+

使用LINQ表达我想找到每一个最新的内容类型，所以结果应该是

Using a LINQ expression I want to find the newest content of each type, so the result should be

Some text | TypeA 
A dog     | TypeB

我已经尝试了一些事情，但指出非工作表现没有意义的。

I have tried a few things but no point in pointing out non-working expressions.

推荐答案

如果你想获得整个帖子。你可以试试这个：

If you want to get the whole Posts. You can try this:

var query = Posts.GroupBy(p => p.Type)
                  .Select(g => g.OrderByDescending(p => p.Date)
                                .FirstOrDefault()
                   )

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