通过表头PHP从mysql获取数据

Question

我有这样的代码：

$start  = new DateTime('first day of this month');
$end    = new DateTime('first day of this month + 1 month');
$period = new DatePeriod($start, new DateInterval('P1D'), $end);
foreach($period as $day){
?>



<th><?php echo $day->format('Y-M-d')."\n"; ?></th>

<?php
}
?>

它将显示包含本月日期的表格标题

我想从mysql获取数据并按标题排序日期， 这是我的疑问：

$date = mysql_query("SELECT min(TIME(CHECKTIME)) AS timeonly,
                                  max(TIME(CHECKTIME)) AS timeonly2,
                                  DATE(CHECKTIME) AS DateOnly
                                  FROM checkinout
                                            WHERE USERID = $c[USERID] AND CHECKTIME = $day
                                            GROUP BY DateOnly
                                            ORDER BY CHECKTIME ASC");

我知道这是错的， 但我不知道如何对CHECKTIME进行排序，以便它们从标题中显示相应的日期？

该查询该怎么办？

WHERE USERID = $c[USERID] AND CHECKTIME = $day