Вопрос к знатокам баз данных

procedure UpdateStatistic(Grid: TdbStringGridEx);
var
  WorkmanData: TDataSet;
  WorkmanData2: TDataSet;
  col, row : integer;
  s: string;
  ShiftCount: integer;
  ShiftProc: integer;
  MaxSP: integer;
begin
  SQLQuery('select workman.id, workman.code, ( select count(id) from shiftbook where shiftbook.id_workman = workman.id ) as shift from workman order by code',WorkmanData);
  SQLQuery('select * from workman order by code',WorkmanData2);

  MaxSP := SQLExecute('select IntersectionRate from config');

//  ShowMessage(  INTTOSTR(MaxSP) );

  Grid.Columns.Clear;
  try
     Grid.Columns.Add(TNxTextColumn);
   except
   end;
  Grid.Columns[0].Width := 40;
  Grid.FixedCols := 1;

  Grid.Columns[0].Color := clbtnFace;
  while not WorkmanData.Eof do
  begin
    try
      Grid.Columns.Add(TNxTextColumn);
    except
    end;
    Grid.Columns[Grid.Columns.count-1].Header.Caption := WorkmanData.FieldByName('code').asString;
    Grid.Columns[Grid.Columns.count-1].Color := clWhite;
    Grid.Columns[Grid.Columns.count-1].Width := 40;

    Grid.AddRow;
    Grid.Cells[0, Grid.RowCount-1] := WorkmanData.FieldByName('code').asString;

    //
    WorkManData.next;
  end;

  row := 0;
  WorkmanData.First;
  while not WorkmanData.Eof do
  begin
    col := 1;
    WorkmanData2.First;
    while not WorkmanData2.Eof do
    begin
      if WorkmanData.FieldByName('id').asString = WorkmanData2.FieldByName('id').asString then
        Grid.Cells[col, row] := '-'
      else
      begin
    // совместные выходы
      s := ' select count(*) from shiftbook left join shiftbook as sb2 on sb2.id_shift = shiftbook.id_shift'+
         ' where shiftbook.id_workman = '+WorkmanData.FieldByName('id').asString+' and sb2.id_workman = '+WorkmanData2.FieldByName('id').asString;
      ShiftCount := SQLExecute(s);
      if WorkManData.FieldByName('shift').asInteger = 0 then
        ShiftProc := 0
      else
        ShiftProc := trunc( ShiftCount / WorkManData.FieldByName('shift').asInteger * 100 );
      //
       Grid.Cells[col, row] := inttostr(ShiftProc)+'%';
       if ShiftProc > MaxSP then
         Grid.Cell[col, row].color := RGB(255,200,200);
      end;
      col := col + 1;
      WorkManData2.next;
    end;
    //
    row := row + 1;
    WorkManData.next;
  end;

end;