for (int id = 0; id < 200; id++)
        {
            var foundID = from r in dv.AsEnumerable()
            orderby r.Field<string>("Log Date")
            where r.Field<int>("User ID") ==  id
            select r;

            foreach (var row in foundID)
            {

                var foundDate = overtime.Select("ID = '" + id
                + "' AND 'Log Date' = '"+row.Field<string>("Log Date")+"'");





                if(foundDate.Count() == 0){
                    Rowq["ID"] = row.Field<int>("User ID");
                    Rowq["Date"] = row.Field<string>("Log Date");
                    overtime.Rows.Add(Rowq);
                    Rowq = overtime.NewRow();

                    id++;
                }
                else { continue; }


            }

0000000002  Name1   2014/10/16  09:03:13    F1
0000000002  Name1   2014/10/16  17:02:20    F2
0000000002  Name1   2014/10/18  08:38:42    F1
0000000002  Name1   2014/10/18  16:55:02    F2
0000000002  Name1   2014/10/19  09:05:21    F1
0000000004  Name2   2014/10/01  00:07:09    F2
0000000004  Name2   2014/10/01  15:46:49    F1
0000000004  Name2   2014/10/02  00:09:52    F2

ID         Name        Date       F1           F2
     0000000002    Name1    2014/10/16  09:03:13     17:02:20
     0000000002    Name1    2014/10/18  08:38:42     16:55:02
     etc..