几个月前你可能已经解决了这个问题，但我这是我的2美分，因为我认为这是一个有趣的问题

我不认为标准的WP搜索查询可以用于搜索具有（帖子类型A）或（帖子类型B和类别C）的帖子。但是，您可以使用将自定义where子句传递给查询posts_where 筛选以处理此类情况。

我觉得这样应该行得通，

add_filter( \'posts_where\' , \'my_posts_where\', 10, 2 );
function my_posts_where( $where, $query ) {

    if ( is_admin() || ! is_search() || ! is_main_query() ) {
        return $where;
    }

    // check that requred $_GET parameters are set
    if ( ! empty( $_GET[\'post_type\'] ) || \'bwps\' !== $_GET[\'post_type\'] ) {
        return $where;
    }

    if ( empty( $_GET[\'s\'] ) ) {
        return $where;
    }

    // return custom where clause
    global $wpdb;
    $sql = "
        AND (
            {$wpdb->posts}.post_title LIKE \'%%%s%%\' OR
            {$wpdb->posts}.post_name LIKE \'%%%s%%\'
        )
        AND
            {$wpdb->posts}.post_status = \'publish\'
        AND
            (
                (
                    {$wpdb->posts}.post_type = \'bwps\'
                ) OR
                (
                    {$wpdb->posts}.post_type = \'page\'
                    AND
                    {$wpdb->posts}.ID IN (
                        SELECT {$wpdb->posts}.ID FROM {$wpdb->posts} AS p
                        INNER JOIN {$wpdb->term_relationships} AS tr ON (p.ID = tr.object_id)
                        INNER JOIN {$wpdb->term_taxonomy} AS tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
                        INNER JOIN {$wpdb->terms} AS t ON (t.term_id = tt.term_id)
                        WHERE
                            p.post_status = \'publish\'
                            AND t.term_id = %d
                            AND tt.taxonomy = \'category\'
                    )
                )
            )
    ";

    $search_phrase = \'%\' . $_GET[\'s\'] . \'%\';
    $term_id = 1;

    return $wpdb->prepare(
        $sql,
        $search_phrase,
        $search_phrase,
        $term_id
    );
}