C# Outer Apply in LINQ

Question

How can I achieve Outer Apply in LINQ? I\'m having a bit of a problem.

Here\'s the SQL Query I\'m using.

SELECT u.masterID
      ,u.user
      ,h.created         


        

Answer 1

Outer Apply produces results of left outer join,
the query should be:

var q =
from u in db.Users
join h in db.UserHistory on u.masterID equals h.masterID into ps
from p in ps.DefaultIfEmpty()
select new { 
    masterID = u.masterID
    ,user = u.user
    ,created = ps.OrderByDescending(x=>x.created).FirstOrDefault()==null?null:ps.OrderByDescending(x=>x.created).First().created
};

Answer 2

from u in Users
join UserHistory on u.masterID equals h.masterID into h
select new {u.masterID, u.user, h.created.OrderByDescending().First()}

Answer 3

from u in Users 
join UserHistory on u.masterID equals h.masterID into h 
select new {
  u.masterID,
  u.user,
  Created = h.Select(x => x.created).OrderByDescending(c => c).FirstOrDefault()
}

Or, with an association:

from u in Users
let created = u.UserHistories.Select(x => x.created).OrderByDescending(c => c).FirstOrDefault()
select new
{
  u.masterID,
  u.user,
  Created = created
}