Cортировка в DBGrid

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, DBGrids, DB, ADODB, StdCtrls;
 
type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADOTable1: TADOTable;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    ADOTable1key_type: TIntegerField;
    ADOTable1pole1: TStringField;
    ADOTable1jihu: TMemoField;
    ADOTable1int_type: TIntegerField;
    ADOTable1flat_type: TFloatField;
    ADOTable1cur_type: TBCDField;
    procedure DBGrid1TitleClick(Column: TColumn);
  private
    { Private declarations }
  public
  i : integer;
   a:integer;
   d:integer;
   b:integer;
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
 
 
procedure TForm1.DBGrid1TitleClick(Column: TColumn);
begin
 if a<2 then
    begin
    if i=2 then
    begin
      i:= 1;
      adotable1.Sort:=Column.FieldName + ' ASC';
      adotable1.Refresh;
    end
    else
    begin
      i:= 2;
      adotable1.Sort:=Column.FieldName + ' DESC';
      adotable1.Refresh;
 
    end;
    a:=a+1;
    end
    else
    begin
    a:=0;
      adotable1.Close;
      adotable1.Open;
      adotable1.Refresh;
    end;
   
 
end;
 
end.

DataModule11.TJurList.Filtered:=true;
DataModule11.TJurList.Filter:='Дата выдачи путевого листа>='+''''+DatetoStr(DateTimePicker1.Date)+''' AND
'Дата выдачи путевого листа<='''+DatetoStr(DateTimePicker2.Date)+''';

DataModule11.TJurList.Filtered:=true;
DataModule11.TJurList.Filter:='[Дата выдачи путевого листа]>='+''''+DatetoStr(DateTimePicker1.Date)+''' AND
''[Дата выдачи путевого листа]<='''+DatetoStr(DateTimePicker2.Date)+''';

DataModule11.TJurList.Filter:='[Дата выдачи путевого листа]>='+''''+DatetoStr(DateTimePicker1.Date)+''' AND
''[Дата выдачи путевого листа]<='''+DatetoStr(DateTimePicker2.Date)+''';

DataModule11.TJurList.Filtered:=true;

ADOQuery1.Active:=false;
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add('SELECT* FROM tabl1 WHERE [дата] BETWEEN :StartDate AND :FinishDate ');
ADOQuery1.Parameters.ParamByName('StartDate').Value:=DateTimePicker1.DateTime;
ADOQuery1.Parameters.ParamByName('FinishDate').Value:=DateTimePicker2.DateTime;
ADOQuery1.Active:=true;

DateTimePicker1.Time:=StrToTime('0:00:00');
DateTimePicker2.Time:=StrToTime('0:00:00');