LINQ (to Oracle) - Row_Number() Over Partition By - sql-server

Question

This is a possible duplicate of other Partition By + Rank questions but I found most of those questions/answers to be too specific to their particular business logic. What I'm looking for is a more general LINQ version of the following type of query:
SELECT id,
field1,
field2,
ROW_NUMBER() OVER (PARTITION BY id
ORDER BY field1 desc) ROWNUM
FROM someTable;
A very common thing we do with this is to wrap it like in something like this:
SELECT id,
field1,
field2
FROM (SELECT id,
field1,
field2,
ROW_NUMBER() OVER (PARTITION BY id
ORDER BY field1 desc) ROWNUM
FROM someTable)
WHERE ROWNUM = 1;
Which returns the row containing the highest value in field1 for each id. Changing the order by to asc of course would return the lowest value or changing the rank to 2 will get the second highest/lowest value etc, etc. Is there a way to write a LINQ query that can be executed server side that gives us the same sort of functionality? Ideally, one that as performant as the above.
Edit:
I've tried numerous different solutions after scouring the web and they all end up giving me the same problem that Reed's answer below does because the SQL generated includes an APPLY.
A couple examples I tried:
from p in db.someTable
group p by p.id into g
let mostRecent = g.OrderByDescending(o => o.field1).FirstOrDefault()
select new {
g.Key,
mostRecent
};
db.someTable
.GroupBy(g => g.id, (a, b) => b.OrderByDescending(o => o.field1).Take(1))
.SelectMany(m => m);
Both of these result in very similar, if not identical, SQL code which uses an OUTER APPLY that Oracle does not support.

Answer 1

You should be able to do something like:
var results = someTable
.GroupBy(row => row.id)
.Select(group => group.OrderByDescending(r => r.id).First());
If you wanted the third highest value, you could do something like:
var results = someTable
.GroupBy(row => row.id)
.Select(group => group.OrderByDescending(r => r.id).Skip(2).FirstOrDefault())
.Where(r => r != null); // Remove the groups that don't have 3 items

Answer 2

an alternative way, by using a subquery which separately gets the maximum field1 for each ID.
SELECT a.*
FROM someTable a
INNER JOIN
(
SELECT id, max(field1) max_field
FROM sometable
GROUP BY id
) b ON a.id = b.ID AND
a.field1 = b.max_field
when converted to LINQ:
from a in someTable
join b in
(
from o in someTable
group o by new {o.ID} into g
select new
{
g.Key.ID,
max_field = g.Max(p => p.field1)
}
) on new {a.ID, a.field1} equals new {b.ID, field1 = b.max_field}
select a