EE4 List attendees shortcode (basic)

gistfile1.txt

//shortcocde is:   [ee_attendee_list event_id=""]

//This would be added to either the themes functions.php or a custom functions plugin


add_shortcode( 'ee_attendee_list', 'ee_attendee_list' );
 
function ee_attendee_list($atts){

	$post_id = $atts['event_id'];
    global $wpdb, $post;
    
    if(is_singular()){
        echo '<ul class="attendee-list">';
    
        $sql = "SELECT ATT_fname, ATT_lname, ATT_email ";
        $sql .= "FROM {$wpdb->prefix}esp_attendee_meta ";
        $sql .= "INNER JOIN {$wpdb->prefix}esp_registration ";
        $sql .= "ON {$wpdb->prefix}esp_attendee_meta.ATT_ID = {$wpdb->prefix}esp_registration.ATT_ID ";
        $sql .= "WHERE {$wpdb->prefix}esp_registration.EVT_ID = %d";
        
        $attendees = $wpdb->get_results( $wpdb->prepare( $sql, $post_id ));
        foreach($attendees as $attendee){
            $fname = $attendee->ATT_fname;
            $lname = $attendee->ATT_lname;
            $email = $attendee->ATT_email;
            $gravatar = get_avatar( $email, '64', 'identicon' );
            $html = '<li>'. $gravatar .'<span>'. $fname .' '. $lname . '</span></li>';
            echo $html;
        }
    
        echo '</ul>';
    }
}