Table doesn't show all data when i filter by a string

I would like to obtain a messageDialog if the id which im filtering is not in the tablemodel i created. the problem is that the ccode works fine without the if, however when i add the if for the messageDialog condition, i realize that the data is found but not shown.

Compare http://prntscr.com/o0z7kqCompare

Code:

public void buscarNumeroSerie (String nserie)

{
 try {

             String [] campos={"NUMERO_SERIE","MARCA","GAVETA"};
             String filtroNS = nserie;
             String NSSQL = "SELECT NUMERO_SERIE,MARCA,GAVETA FROM"
                     + "(SELECT NUMERO_SERIE,MARCA,GAVETA FROM discos_wd "
                     + "UNION "
                     + "SELECT NUMERO_SERIE,MARCA,GAVETA FROM discos_toshiba "
                     + "UNION "
                     + "SELECT NUMERO_SERIE,MARCA,GAVETA FROM discos_seagate "
                     + "UNION "
                     + "SELECT NUMERO_SERIE,MARCA,GAVETA FROM discos_samsung "
                     + "UNION "
                     + "SELECT NUMERO_SERIE,MARCA,GAVETA FROM discos_hitachi )"
                     + "AS TROUBLE WHERE NUMERO_SERIE LIKE '%"+filtroNS+"%'";

            System.out.println(NSSQL); 
                    nsconn = metodosPool.dataSource.getConnection();
                    ModeloTablaLista = new DefaultTableModel(null, campos);
                    stmnt = nsconn.prepareStatement(NSSQL);
                    ResultSet nsrs = stmnt.executeQuery(NSSQL);

            if(nsrs.next()== true){
                    String [] nsfila = new String[3];


                while (nsrs.next())
                    {
                        nsfila[0]=nsrs.getString("Numero_Serie");
                        nsfila[1]=nsrs.getString("Marca");
                        nsfila[2]=nsrs.getString("Gaveta");
                        ModeloTablaLista.addRow(nsfila);
                    }

                        nsrs.close();
                        stmnt.close();
                        tablaDiscosGaveta.setModel(ModeloTablaLista);
           }

           else
              {

                System.err.println("No existen datos asociados");
                     JOptionPane.showMessageDialog(rootPane, "Disco no encontrado, quiere:");
               } 

My idea is that the left image, that which contains the if bit of code show the results i need just like the image on the right. I've tried with "for" sentences, add a new resultSet and change the postion of the if condition without results.