具有错误答案的基本PHP时间计算

$date1 = '2022-01-01';
$date2 = '2022-01-10';

$diff = abs(strtotime($date2) - strtotime($date1));
$days = floor($diff / (60 * 60 * 24));

echo "日期1：$date1<br>";
echo "日期2：$date2<br>";
echo "日期差：$days 天";

$date1 = new DateTime('2022-01-01 10:00:00');
$date2 = new DateTime('2022-01-01 15:30:00');

$interval = $date1->diff($date2);
$hours = $interval->h;

echo "日期1：".$date1->format('Y-m-d H:i:s')."<br>";
echo "日期2：".$date2->format('Y-m-d H:i:s')."<br>";
echo "小时差：$hours 小时";