LINQ to SQL: Left join on multiple columns

Question

First of all, I have searched google/SO, checked some examples, but I didn\'t manage to write the proper linq expression:

This is how my working sql query lo

Answer 1

You have to use .DefaultIfEmpty() to perform a left join. Then you need to decide what to do in case the right table produces null. You can use a ternary operator ( ? : ) for that.

var result = 
    (from p in _db.Places
    join v in _db.VoteLogs
    on new { p.Id, userId } equals new { v.PlaceId, v.UserId } into LEFTJOIN
    from result in LEFTJOIN.DefaultIfEmpty()
    where p.Public == 1
    select new
    {
        Id = p.Id,
        UserId = p.UserId,
        X = p.X,
        Y = p.Y,
        Titlu = p.Titlu,
        Descriere = p.Descriere,
        Public = p.Public,
        Votes = p.Votes,
        DateCreated = p.DateCreated,
        DateOccured = p.DateOccured,
        UserVoted = result == null ? null /* replace with your value */ : x.Vote
    }).AsQueryable();

return result;