สอบถามการคิวรี่ ค่าจากดาต้าเบสลง gridview โดยใช้ linq ครับ

var std = from stdq in db.student
                      from teacq in db.teacher
                      from comq in db.company
                      where (stdq.major_fk == nummaj && stdq.teacher_fk == teacq.t_id && stdq.company_fk == comq.comp_id) || (stdq.major_fk == nummaj && stdq.teacher_fk == null && stdq.company_fk == null)
                      select new
                      {
                          id = stdq.std_id,
                          pass = stdq.std_password,
                          sname = stdq.std_sname_th,
                          fname = stdq.std_fname_th,
                          lname = stdq.std_lname_th,
                          tid = stdq.teacher_fk,
                          tname = teacq.t_fname,
                          comid = stdq.company_fk,
                          comname = comq.comp_name
                      };

            GridView1.DataSource = std.ToList();
            GridView1.DataBind();

Label lblteacher = (Label)(e.Row.FindControl("lblteacher"));
            if (lblteacher != null)
            {
                if (DataBinder.Eval(e.Row.DataItem, "tid") == null)
                {
                    lblteacher.Text = "ยังไม่ได้เลือก";
                }
                else
                {
                    lblteacher.Text = (string)DataBinder.Eval(e.Row.DataItem, "tname");
                }
            }

            Label lblcompany = (Label)(e.Row.FindControl("lblcompany"));
            if (lblcompany != null)
            {
                if (DataBinder.Eval(e.Row.DataItem, "comid") == null)
                {
                    lblcompany.Text = "ยังไม่ได้เลือก";
                }
                else
                {
                    lblcompany.Text = (string)DataBinder.Eval(e.Row.DataItem, "comname");
                }
            }