对于简单的元查询，可以执行以下操作：

function wpa_47150( &$query ) {
  if(!is_admin()){
    set_query_var(\'meta_key\', \'test_field\');
    set_query_var(\'meta_value\',\'bacon\');
  }
}
add_action(\'pre_get_posts\',\'wpa_47150\');

function wpa_47150( &$query ) { 

    if(!is_admin() && is_post_type_archive( \'test_post_type\' )){    
        $metaq = ( array ( array(
            \'key\' => \'test_field\',
            \'value\' => array( 10, 50 ),
            \'type\' => \'numeric\',
            \'compare\' => \'BETWEEN\'
            ))
        );
        set_query_var(\'meta_query\', $metaq );
    }
}

add_action(\'pre_get_posts\',\'wpa_47150\');

要仅显示设置了内容过滤器的字段，唯一的问题可能是为每篇文章加载自定义字段时会有一个单独的查询：

function muvice_custom_content($content) {
    if ( \'line\' == get_post_type() ) { 
        wp_enqueue_style( \'muvice_stylesheet\',plugin_dir_url(__FILE__).\'muvice.css\' );

        $custom_fields = get_post_custom(get_the_ID());

        $newcontent = \'<div class ="part_wrapper">\';
        $newcontent .=\'<div class="part1">\'.$custom_fields[\'part1\'][0].\'</div>\';
        $newcontent .=\'</div><!-- .part_wrapper -->\';

        $original = $content;
        $content = $original.$newcontent;
    }

    return $content;
}
add_filter(\'the_content\', \'muvice_custom_content\',1);