管理PHP,MySQL等日期的最佳方法是什么？

$date = new DateTime();
echo $date->format('Y-m-d H:i:s');

CREATE TABLE example (
    id INT AUTO_INCREMENT PRIMARY KEY,
    datetime DATETIME
);

INSERT INTO example (datetime) VALUES ('2022-01-01 12:34:56');

SELECT * FROM example WHERE datetime = '2022-01-01 12:34:56';

$date1 = new DateTime('2022-01-01');
$date2 = new DateTime('2022-01-10');
$interval = $date1->diff($date2);
echo $interval->days;