Entity Framework select one of each group by date

c# entity-framework linq

Question

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 |
+----+--------------------------+-------+------------+

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

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

1
28
2/18/2015 4:06:47 PM

Accepted Answer

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()
                   )
63
4/29/2013 9:13:08 AM

Popular Answer

I suppose you can group your Posts rows by type and then select first content from descending ordered by date collection of that type

from row in Posts 
group row by row.type 
into g
select new
{       
    Content  = (from row2 in g orderby row2.date descending select row2.content).FirstOrDefault(),
    Type = g.Key
}


Related Questions





Related

Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow