Нахождение максимального элемента в DBGrid

procedure TForm1.Button1Click(Sender: TObject);
var max, i: integer;
begin
max:=0;
For i:=0 to Table1.FieldCount-1 do
if Table1Id.Value > max then max:=Table1Id.Value;
max:=max+1;
Table1.Append;
Table1Id.Value:=max;
Table1Name.Value:=Edit1.Text;
Table1.Post;
end;

procedure TForm1.Button1Click(Sender: TObject);
var max_id: integer;
begin
 
  ADOQuery1.SQL.Clear;
  ADOQuery1.SQL.Add('SELECT MAX(ID) AS max_id FROM TAvto');
  ADOQuery1.Open;
  max_id:=ADOQuery1.FieldByName('max_id').AsInteger+1;
  ADOQuery1.Close;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  ADOQuery1.SQL.Clear;
  ADOQuery1.SQL.Add('SELECT MAX(Key) AS max_id FROM TAvto');
  ADOQuery1.Open;
  max_id:=ADOQuery1.FieldByName('max_id').AsInteger+1;
  ADOQuery1.Close;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  {ADOQuery1.SQL.Clear;
  ADOQuery1.SQL.Add('SELECT max(Key1) AS max_id FROM TAvto');
  ADOQuery1.Open;
  max_id:=ADOQuery1.FieldByName('max_id').AsInteger+1;
  ADOQuery1.Close;}
  ADOQuery1.Append;
  ADOQuery1Key1.Value:=3;
  ADOQuery1Name.Value:=Edit1.Text;
  ADOQuery1.Post;
end;