lex

  procedure TForm1.Button1Click(Sender: TObject);
begin

DM.ADOQuery1.Close;
DM.ADOQuery1.Active := false;
DM.ADOQuery1.SQL.Clear;
With DM.ADOQuery1.SQL do begin
 Add('Select D.* from devices D ');
 Add( 'where  tip like '''+Combobox1.Text+''' end  firm like '''+Combobox2.Text+''' ;');

end;
DM.ADOQuery1.ExecSQL;
DM.ADOQuery1.Active := true;
Reff(Self);
end;