我有一个自定义的帖子类型，我还需要一个自定义搜索。我想对文章标题和两个自定义字段进行索引/查询。我找到了只针对标题和自定义字段的解决方案，但不同时针对这两个字段，所以我尝试将它们结合起来。为什么这样不行？

function custom_search( $search, &$wp_query )
{
    global $wpdb;
    if ( empty( $search ) )
        return $search; // skip processing - no search term in query
    $q = $wp_query->query_vars;
    $n = ! empty( $q[\'exact\'] ) ? \'\' : \'%\';
    $search =
    $searchand = \'\';
    foreach ( (array) $q[\'search_terms\'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}($wpdb->posts.post_title LIKE \'{$n}{$term}{$n}\')";
        $searchand = \' AND \';
    }
    $searchand = \' OR \';
    foreach ( (array) $q[\'search_terms\'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}(($wpdb->m.meta_key = \'wpcf-kurzbeschreibung\') AND (m.meta_value  LIKE \'{$n}{$term}{$n}\'))";
        $searchand = \' AND \';
    }

    if ( ! empty( $search ) ) {
        $search = " AND ({$search}) ";
        if ( ! is_user_logged_in() )
            $search .= " AND ($wpdb->posts.post_password = \'\') ";
    }
    return $search;
}
add_filter( \'posts_search\', \'custom_search\', 500, 2 );