/**
 * @param $beginDate  开始日期
 * @param $endDate    结束日期
 * @return string
 */
function timeCalculation($beginDate, $endDate)
{
    $subTime = strtotime($endDate) - strtotime($beginDate);
    $day = $subTime > 86400 ? floor($subTime / 86400) : 0;
    $subTime -= $day * 86400;
    $hour = $subTime > 3600 ? floor($subTime / 3600) : 0;
    $subTime -= $hour * 3600;
    $minute = $subTime > 60 ? floor($subTime / 60) : 0;
    $subTime -= $minute * 60;
    $second = $subTime;

    $dayText = $day ? $day . '天' : '';
    $hourText = $hour ? $hour . '小时' : '';
    $minuteText = $minute ? $minute . '天' : '';
    $date = $dayText . $hourText . $minuteText . $second . '秒';
    return $date;
}

$result = $this->timeCalculation('2020-08-06 11:00:00', '2020-08-10 12:10:01');
echo $result;    // 4天1小时10天1秒