在PHP中，先按日期键排序数组值，然后再按时间键排序

usort($data, function($a, $b) {
    // 首先按日期键排序
    $dateComparison = strcmp($a['date'], $b['date']);
    
    // 如果日期键相同，则按时间键排序
    if ($dateComparison == 0) {
        return strcmp($a['time'], $b['time']);
    }
    
    return $dateComparison;
});

$data = array(
    array('date' => '2022-01-01', 'time' => '09:00:00'),
    array('date' => '2022-01-01', 'time' => '10:00:00'),
    array('date' => '2022-01-02', 'time' => '08:00:00'),
    array('date' => '2022-01-02', 'time' => '09:30:00'),
    array('date' => '2022-01-03', 'time' => '11:00:00'),
    array('date' => '2022-01-03', 'time' => '12:00:00')
);

usort($data, function($a, $b) {
    $dateComparison = strcmp($a['date'], $b['date']);
    
    if ($dateComparison == 0) {
        return strcmp($a['time'], $b['time']);
    }
    
    return $dateComparison;
});

print_r($data);

Array
(
    [0] => Array
        (
            [date] => 2022-01-01
            [time] => 09:00:00
        )

    [1] => Array
        (
            [date] => 2022-01-01
            [time] => 10:00:00
        )

    [2] => Array
        (
            [date] => 2022-01-02
            [time] => 08:00:00
        )

    [3] => Array
        (
            [date] => 2022-01-02
            [time] => 09:30:00
        )

    [4] => Array
        (
            [date] => 2022-01-03
            [time] => 11:00:00
        )

    [5] => Array
        (
            [date] => 2022-01-03
            [time] => 12:00:00
        )

)