基于@birgire总是有用的评论，我确实为您编写了一个变通方法。我要做的是首先找到与搜索字符串匹配的术语。然后，根据找到的术语，我将在这些术语中进行查询。

function wpse_posts_by_tagname( $string ) {

    // Let\'s find every tag that has \'coffee\' in it\'s name
    $term_args = array(
        \'taxonomy\'             => \'post_tag\',
        \'fields\'               => \'ids\',
        \'name__like\'           => $string,
        // \'description__like\' => $string, // You can also search in description. 
        // \'search\'            => $string, // We can even search in the term\'s name! 
    );
    $terms = get_terms( $term_args );

    // Let\'s make an array of term IDs
    if ( empty( $terms ) || is_wp_error( $terms ) )
        esc_html_e( \'No matches found\', \'text-domain\' );

    // Alright we got\'em, now query based on these
    $query_args = array(
        \'post_type\'      => \'post\',
        \'tag__in\'        => (array) $terms,
        \'posts_per_page\' => 10 // Optional limitation of posts per page
    );
    $tag_query = new WP_Query( $query_args );

    if( $tag_query->have_posts() ){
        while( $tag_query->have_posts() ){
            $tag_query->the_post();
            the_title( 
                sprintf( \'<h2><a href="%s">\', esc_url( get_permalink() ) ),
                \'</a></h2>\' 
            );
        }
        wp_reset_postdata();
    } else {
        esc_html_e( \'No matches found\', \'text-domain\' );
    }
}