grouping with remote grouping for join not working

Hello,

I am using LinqToDb as database framework (if you use it you don’t want to use EF again 😃 ). Everything works fine for a normal query with a dx-grid. Buit if I try to create a left join query and access the header filter, the created query will fail.

This is my join:

var r = from k in this.GetTable<Person>() join ks in this.GetTable<Student>() on new Tuple<int, string>(k.Id, k.Number.ToString()) equals
               new Tuple<int, string>(ks.Id, ks.Number) into joinedTable
               from g in joinedTable.DefaultIfEmpty()
                    select new Person(k) {
            IsBlocked = (k.StatusBitmask & 0x80) != 0, IsBlockedStudent = (g.StatusBitmask & 0x80) != 0 };

The reault in the grid works perfect:

[HttpGet]
      [Route("with-filter")]
      public HttpResponseMessage GetFiltered( [FromUri]DataSourceLoadOptions loadOptions)
      {
         LoadResult result = null;
         try
         {
            loadOptions.RemoteSelect = true;
            loadOptions.RequireTotalCount = true;
            using(var db = DbContext())
            {
               // Get joined result will retrieve the joined query.
               result = DataSourceLoader.Load(db.GetJoinedResult(), loadOptions);
            }            
         }
         catch (Exception ex)
         {
            return new HttpResponseMessage(HttpStatusCode.InternalServerError);
         }
         
         return Request.CreateResponse(result);
      }

The resulting sql is the following:

-- Firebird
SELECT
	Count(*) as c1,
	0 as c2
FROM
	PERSON k1
		LEFT JOIN STUDENT joinedTable ON k1.ID = joinedTable.ID AND Cast(k1.NUMBER as VarChar(11) CHARACTER SET UNICODE_FSS) = joinedTable.NUMBER
ORDER BY
	0

This does not work, because the order by is not valid. And I am not sure if this is the desired query?

[frankiDotNet]

Checked this with the guys at LinqToDb. It is the cause of using the copy constructor in the GetJoinedResult(), so the grouping had no data to group. Without using a copy constructor, but setting the properties directly in the select statement, this works. Thanks for your work!

[frankiDotNet]

Nit 100% sure, but this could be a linq2db bug.