Question

I cant get the fallowing request working in Mono:
Without joins it would work.
when I only select t1 it also works, but I cant select something from both tables.
I think I want a left join, where I always have entries in t1 and IF the NameOfFile matches FileName then I want to have the tables joined.

Extra Question: When is my query executed? When I run the foreach loop?

var result = (
            from t1 in db.Table1 
            join t2 in db.Table2 on t1.FileName equals t2.NameOfFile
            into joinDep                
            from t3 in joinDep.DefaultIfEmpty () 
            select new 
            {
            Time = t1.WriteTime,
            Name = t2.NameOfFile

            }
        )
        .OrderByDescending (c => c.Time.Date)
        .Take (10);
foreach (var entry in result)
{
    Console.WriteLine (entry.Name );
}

Answer 1

Use this:

var query = from t1 in db.Table1 
            join t2 in db.Table2 on t1.FileName equals t2.NameOfFile into gj
            from joinDep in gj.DefaultIfEmpty ()
            select new 
            {
               Time = t1.WriteTime,
               Name = joinDep.NameOfFile
            };

var result = query.OrderByDescending (c => c.Time.Date)
                .Take (10);

Yes. Take uses deferred execution.