DateTime::add 会添加小时，即使间隔应该仅为秒

这来自我之前关于获取指定数据集的平均时间间隔的问题，[位于此处][1]。我将再次发布整个函数：

function getATBData($siteID, $fromDate, $toDate)
{
    global $pdo;

    $ATBarray = array();
    $maxATB;
    $minATB;
    $avgATB;
    $totalATB=new DateTime("@0");
    $totalEvents=0;
    $timetable;

    $query = "SELECT id, siteID, start_time, end_time FROM atb_log WHERE siteID=:siteID AND (start_time BETWEEN :fromDate AND :toDate) AND (end_time BETWEEN :fromDate AND :toDate)";
    $stmt = $pdo->prepare($query);
    $stmt->bindParam(":siteID", $siteID);
    $stmt->bindParam(":fromDate", $fromDate);
    $stmt->bindParam(":toDate", $toDate);
    $stmt->execute();

    foreach ($stmt as $row)
    {
        $timeDiff = date_diff(new DateTime($row['start_time']),new DateTime($row['end_time']), true); //force absolute
        if(!isset($maxATB) OR dateIntervalInSeconds($timeDiff) > dateIntervalInSeconds($maxATB))
            $maxATB = $timeDiff;
        if(!isset($minATB) OR dateIntervalInSeconds($timeDiff) < dateIntervalInSeconds($minATB))
            $minATB = $timeDiff;
        $totalATB->add($timeDiff);
        echo "added " . $timeDiff->format("%H:%I:%S") . " total is now: " . $totalATB->format("H:i:s") . "<br />";
        $totalEvents++;
    }

    if($totalEvents!=0)
    {
        $avgATB = average_time($totalATB->format("H:i:s"),$totalEvents,0);
    }
    else
    {
        $avgATB=0;
        $maxATB=new DateInterval('PT0S');
        $minATB=new DateInterval('PT0S');
    }
    //$avgSeconds = new DateInterval("PT" . $avgATB . "S");
    $ATBarray['max'] = $maxATB->format("%H:%I:%S");
    $ATBarray['min'] = $minATB->format("%H:%I:%S");
    $ATBarray['avg'] = $avgATB;
    $ATBarray['total'] = $totalATB->format("H:i:s");
    $ATBarray['events'] = $totalEvents;

    return $ATBarray;

}

给定这个函数，我添加了一个输出语句来尝试调试为什么我的总时间得到这么大的时间间隔（当大多数值都是很少的秒数时），这就是它的输出：

added 00:00:02 total is now: 01:00:02
added 00:00:00 total is now: 02:00:02
added 00:00:01 total is now: 03:00:03
added 00:00:01 total is now: 04:00:04
added 00:00:00 total is now: 05:00:04
added 00:00:02 total is now: 06:00:06
added 00:00:00 total is now: 07:00:06

等等。所以看起来，尽管增加的时间只有几秒钟，但每次都会增加一个小时。致电给add() on $timeDiff上面是我添加的方式。

所以问题是 - 有没有一种不同的方式来调用add()函数只添加秒数？我是否错误地称呼它？

嗯，以秒为单位的平均差异，如果您的数据库可以为您提供 PHP 代码段，为什么会这样：

SELECT 
  SEC_TO_TIME(MAX(TIME_TO_SEC(TIMEDIFF(end_time,start_time)))) AS max_timediff,
  SEC_TO_TIME(MIN(TIME_TO_SEC(TIMEDIFF(end_time,start_time)))) AS min_timediff,
  SEC_TO_TIME(AVG(TIME_TO_SEC(TIMEDIFF(end_time,start_time)))) AS avg_timediff,
  SEC_TO_TIME(SUM(TIME_TO_SEC(TIMEDIFF(end_time,start_time)))) AS sum_timediff,
  COUNT(id) as total_events
FROM atb_log 
WHERE 
  siteID=:siteID 
  AND start_time > :fromDate
  AND end_time < :toDate

根据您的喜好格式化这些最小/最大/平均/总秒数。