我尝试从请求中获取一些值并在循环中显示它。我已经在另一个函数中使用了这个系统，它工作正常，但在这个函数中没有。我得到消息：Warning: Invalid argument supplied for foreach()

 function mic_services_shortcode($atts = [], $content = \'\') {
        global $post;
        $id = $post->post_name;
        $id = explode("-s", $id);
        global $wpdb;
        $prepare = $wpdb->prepare(\'SELECT DISTINCT wp_mic_keyword.keyword as keyword, wp_mic_keyword.image as image, wp_mic_keyword.texte as texte\'. \'  FROM wp_mic_keyword INNER JOIN wp_mic_rel_key_ser ON id_keyword where id_service=%d;\', $id);
        $results = $wpdb->get_results($prepare);
        ob_start();
        echo \'<div style="border: 1px solid black;>\';
        foreach ($results as $key) { 
           echo 
           \'<div>\';      
            echo $key->keyword.\'<br>\';
            echo $key->image ."<br>";
            echo
            $key->texte;        
            echo \'</div>\';
        }
        echo \'</div>\';
        $html_form = ob_get_clean();
        return $html_form;
    }