public static ArrayList<Subcategorias> sqlSelect(){
        ArrayList<Subcategorias> subcat = new ArrayList();
        if(!BD.getInstance().sqlSelect("SELECT sc.nombre, sc.idsubcategorias FROM subcategorias sc INNER JOIN cat_subcat_tit_attr_descr pr ON pr.subcategorias_id = sc.idsubcategorias GROUP BY sc.nombre;")){
            return subcat;
        }        
        while(BD.getInstance().sqlFetch()){
            subcat.add(new Subcategorias(BD.getInstance().getInt("idsubcategorias")
                                        ,BD.getInstance().getString("nombre") ));
        }
        return subcat;
    }