对于针对单个日期字段的查询，可以使用 BETWEEN 操作员：

$sql = "SELECT * FROM " . $DB->prefix('cal_event') . " WHERE 
        DATE(FROM_UNIXTIME(event_time)) BETWEEN '$date1' AND '$date2'
        ORDER BY event_organiser ASC";

对于针对多个日期字段（如开始时间和结束时间）的查询，您需要检查 => 以及 <= :

$sql = "SELECT * FROM " . $DB->prefix('cal_event') . " WHERE 
        DATE(FROM_UNIXTIME(event_start)) >= '$todayint' AND
        DATE(FROM_UNIXTIME(event_end)) <= '$todayint'
        ORDER BY event_organiser ASC";

在这两种情况下，你都想利用 AND 而不是 OR .

使用 BETWEEN ( column BETWEEN value1 AND value2 )

$time = time(); 
$todayint=date("Y-m-d", strval($time));

$sql = "SELECT * FROM " . $DB->prefix('cal_event') 
     . "WHERE DATE(FROM_UNIXTIME(event_start))
        BETWEEN '$todayint' AND '$todayint'
        ORDER BY event_organiser ASC";

使用 >= ( column >= value1 AND column <= value2 )

$time = time(); 
$todayint=date("Y-m-d", strval($time));

$sql = "SELECT * FROM " . $DB->prefix('cal_event') 
     . "WHERE DATE(FROM_UNIXTIME(event_start)) >= '$todayint'
        AND DATE(FROM_UNIXTIME(event_end)) <= '$todayint'
        ORDER BY event_organiser ASC";