Delphi - OnChange

procedure TForm8.Edit4Change(Sender: TObject);

Var vstrCadena:String;

    ADO:TADOQuery;

begin

 While not ADOQuery1.Eof do

    begin

      {Close;

      SQL.Clear;

      SELECT * FROM tabla WHERE campo LIKE '%valor%'}

       ADOQuery1.Close;

       ADOQuery1.SQL.Clear;

       ADOQuery1.SQL.Text:='SELECT * FROM provincias WHERE nombre LIKE '+Edit4.Text+';';

       ADOQuery1.Open;

       ADOQuery1.First;

       ADOQuery1.Active:=true;

end;

procedure TForm8.Edit1Change(Sender: TObject);

begin

  ADOQuery1.Close;

  ADOQuery1.SQL.Clear;

  ADOQuery1.SQL.Text:='SELECT * FROM provincias WHERE codigopostal = '+Edit1.Text;

  ADOQuery1.Open;

  ADOQuery1.Active:=true;

  if not (ADOQuery1.Eof) then

    Edit4.text := ADOQuery1.FieldByName('CIUDAD').AsString;