如何检查和比较日期范围php

$startDate = '2022-01-01';
$endDate = '2022-12-31';
$checkDate = '2022-05-15';

$startTimestamp = strtotime($startDate);
$endTimestamp = strtotime($endDate);
$checkTimestamp = strtotime($checkDate);

if ($checkTimestamp >= $startTimestamp && $checkTimestamp <= $endTimestamp) {
    echo "日期在范围内";
} else {
    echo "日期不在范围内";
}

$startDate1 = '2022-01-01';
$endDate1 = '2022-12-31';

$startDate2 = '2023-01-01';
$endDate2 = '2023-12-31';

if (date('Ymd', strtotime($startDate1)) <= date('Ymd', strtotime($endDate2)) &&
    date('Ymd', strtotime($startDate2)) <= date('Ymd', strtotime($endDate1))) {
    echo "日期范围1和日期范围2有重叠";
} else {
    echo "日期范围1和日期范围2没有重叠";
}