给WordPress 自带的搜索功能添加过滤只搜索文章的标题

如果想让 WordPress 自带的搜索功能只搜索文章标题，让搜索结果更加精确（其实WordPress 自带的搜索功能本来模糊查找就很弱），可以将下面的代码添加到当前主题functions.php中：
用过滤器：posts_search 就可以了。

// 只搜索文章标题
function wpdocs_search_by_title_only( $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($wpdb->esc_like($term));$search .= "{$searchand}($wpdb->posts.post_title LIKE '{$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', 'wpdocs_search_by_title_only', 500, 2);