Delphi and MS Access

unit Unit3;
 
interface
 
uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Grids, Vcl.DBGrids, Data.Win.ADODB, unit4,
  Data.DB;
 
type
  TForm3 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Label2: TLabel;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    a1 : string;
a2 : string;
a3 : string;
a4 : string;
  end;
 
var
  Form3: TForm3;
 
 
 
implementation
 
{$R *.dfm}
 
procedure TForm3.Button1Click(Sender: TObject);    //покупка наша
begin
a1:=Edit1.Text;
a2:=Edit2.Text;
a3:='tov.nt, kontr.nazvp, tov.kol, tov.cena';
a4:='tov.datap <' +a1+' and tov.datap >' +a2;
 
Form4:=TForm4.Create(Application);
Form4.Caption:='Анализ';
Form4.Show;
end;

unit Unit4;
 
interface
 
uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Grids, Vcl.DBGrids, Data.Win.ADODB,
  Data.DB, unit3;
 
type
  TForm4 = class(TForm)
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form4: TForm4;
 
implementation
 
{$R *.dfm}
 
 
procedure TForm4.FormCreate(Sender: TObject);
begin
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add('SELECT'+ Form3.a3 + 'FROM Kontragetn AS kontr, Dogovor AS dog, Tovar AS tov, Pokepka AS pok WHERE'+Form3.a4+';');
ADOQuery1.Active:=True;
end;
 
end.

implementation
uses unit3;
{$R *.dfm}

ADOQuery1.SQL.Add('SELECT'+ Form3.a3 + 'FROM Kontragetn AS kontr, Dogovor AS dog, Tovar AS tov, Pokepka AS pok WHERE'+Form3.a4+';');