Displays an attendee list after the content on the event details page. Displays the gravatar, first name, and last name of each attendee registered for an event. Requires Event Espresso 4.

attendee_list.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

// prints a per event attendee list right after the event details on a single event page
// you can change the action hook that's on the next line to display the list in another location

add_action( 'AHEE_event_details_after_the_content', 'ee_attendee_list' );

function ee_attendee_list(){
    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>';
    }
}