Left Join, Where and GroupBY clause using LINQ C#

Question

I am trying to convert the following query into a LINQ statement.

select u.code, u.id, count(d.unitid) from Unit u
Left join Package d on u.id= d.unitid and d.sstatus = 'Open'
where d.hunit is not null
group by u.code, u.id

This is what I have,

var result = 
    from U in Table<Unit>().ToList()
    join D in Table<Package>().Where(x => x.status == "Open").ToList() on U.Id equals D.UnitId into def1
    from def2 in def1.DefaultIfEmpty()
    group def2 by new
    {
        U.Id,
        U.code
    } into grouped
    select new
    {
        Hmy = grouped.Key.Id,
        Code = grouped.Key.Code,
        TotalPAckages = grouped.Count()
    };

But, in above code, I am also getting the results with UnitId is null in Package table. I am not sure where and how to apply the Where clause part (where d.hunit is not null) in the above LINQ statement.