procedure TForm1.FormShow(Sender: TObject);
begin
    with Query1 do
    begin
        Close;
        SQL.Clear;
        SQL.Add('CREATE TABLE tablename (');
        SQL.Add('Field1 CHARACTER(10),');
        SQL.Add('Field2 CHARACTER(10),');
        SQL.Add('Field3 CHARACTER(10))');
        ExecSQL;
        SQL.Clear;
        SQL.Add('SELECT * FROM tablename');
        Prepare;
        Open;
    end;
end;