PHP列表while循环

如何将列表放入while循环

PHP:

HTML表格：

> while($r = $q->fetch_array(MYSQLI_ASSOC)):  
> echo '<tr>';
> echo '<td>' . $r['title'] . '</td>';  
> echo '<td>' . date('d/M/Y', strtotime($r['eventDate'])) . ' / ' . $r['eventTime'] . '</td>';  
> echo '<td>' . $r['location'] . '</td>';  
> echo '<td>' . array($r['username']) .'</td>';  
> echo '<td ></td>';  
> echo '<td ></td>';  
> echo '</tr>';  
> endwhile;

我想要输出

TITLE        DATE/TIME      LOCATION    USERNAME
=================================================
1       dd/mm/yyy / hh:mm   location    username, username1, username2  
2       dd/mm/yyy / hh:mm   location    username 

或者我需要将foreach置于

echo''上吗。数组（$r['username']）。'
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类似

SELECT title,
       event_date,
       event_time,
       location,
       GROUP_CONCAT(username SEPARATOR ', ') AS username
  FROM bs_events 
  LEFT JOIN bs_reservations
         ON bs_reservations.id_event = bs_events.id   
 GROUP BY bs_reservations.id_event 
          bs_events.title,
          bs_events.event_date,
          bs_events.event_time,
          bs_events.location
 ORDER BY bs_events.eventDate ASC LIMIT 20

编辑

为用户名添加了别名，如

SELECT title,
       event_date,
       event_time,
       location,
       GROUP_CONCAT(username SEPARATOR ', ') AS username
  FROM bs_events 
  LEFT JOIN bs_reservations
         ON bs_reservations.id_event = bs_events.id   
 GROUP BY bs_reservations.id_event 
          bs_events.title,
          bs_events.event_date,
          bs_events.event_time,
          bs_events.location
 ORDER BY bs_events.eventDate ASC LIMIT 20

编辑

为用户名添加了别名
谢谢。。但用户名显示为空。如何放置用户名列表
$r['username']
？谢谢。。但用户名显示为空。如何放置用户名列表
$r['username']
？
SELECT title,
       event_date,
       event_time,
       location,
       GROUP_CONCAT(username SEPARATOR ', ') AS username
  FROM bs_events 
  LEFT JOIN bs_reservations
         ON bs_reservations.id_event = bs_events.id   
 GROUP BY bs_reservations.id_event 
          bs_events.title,
          bs_events.event_date,
          bs_events.event_time,
          bs_events.location
 ORDER BY bs_events.eventDate ASC LIMIT 20