With DM.Query2 Do
              begin
                Close;
                SQL.Clear;
                SQL.Add('Insert into Sub_Ans(Exam_No, Sub_No, Serial_No, Q_Type, Q_Score, Q_Dis, Q_Milt, Q_Ans, Ambig_Ans, Group_Count, Correct_Count, Group_Sum, Low_Sum) ');
                SQL.Add('values (:Exam_No, :Sub_No, :Serial_No, :Q_Type, :Q_Score, :Q_Dis, :Q_Milt, :Q_Ans, :Ambig_Ans, :Group_Count, :Correct_Count, :Group_Sum, :Low_Sum)');
                Parameters.ParamByName('Exam_No').Value:= ComboBox1.Text;
                Parameters.ParamByName('Sub_No').Value:= Copy(ComboBox2.Text, 1, 2);                    if (Trim(StringGrid1.Cells[7, j]) = '') then
                  begin
                    Parameters.ParamByName('Group_Count').Value:= NULL;
                  end
                else
                  begin
                    Parameters.ParamByName('Group_Count').Value:= StringGrid1.Cells[7, j];
                  end;
              end;