带参查询

begin
       Query1.SQL.Clear;
       Query1.SQL.Add('select CustNO, Company, City, State from customer.db');
       Query1.SQL.Add('where country =(:countryName)');
       Query1.Params[0].AsString:=Edit1.Text;
       Query1.ExecSQL;
       Query1.Active:=True;
       Edit1.Text:='';
    end;