我不知道为什么还没有人提到碳。

https://github.com/briannesbitt/Carbon

这实际上是php dateTime的扩展(这里已经使用了)，它有:diffForHumans方法。所以你所需要做的就是:

$dt = Carbon::parse('2012-9-5 23:26:11.123789');
echo $dt->diffForHumans();

更多例子:http://carbon.nesbot.com/docs/#api-humandiff

这个解决方案的优点:

它适用于未来的日期，并将在2个月等时间内返回。 你可以使用本地化来获取其他语言，多元化也很好 如果你开始用碳来做其他事情，处理日期就会变得非常容易。

上面的回答略有修改:

  $commentTime = strtotime($whatever)
  $today       = strtotime('today');
  $yesterday   = strtotime('yesterday');
  $todaysHours = strtotime('now') - strtotime('today');

private function timeElapsedString(
    $commentTime,
    $todaysHours,
    $today,
    $yesterday
) {
    $tokens = array(
        31536000 => 'year',
        2592000 => 'month',
        604800 => 'week',
        86400 => 'day',
        3600 => 'hour',
        60 => 'minute',
        1 => 'second'
    );
    $time = time() - $commentTime;
    $time = ($time < 1) ? 1 : $time;
    if ($commentTime >= $today || $commentTime < $yesterday) {
        foreach ($tokens as $unit => $text) {
            if ($time < $unit) {
                continue;
            }
            if ($text == 'day') {
                $numberOfUnits = floor(($time - $todaysHours) / $unit) + 1;
            } else {
                $numberOfUnits = floor(($time)/ $unit);
            }
            return $numberOfUnits . ' ' . $text . (($numberOfUnits > 1) ? 's' : '') . ' ago';
        }
    } else {
        return 'Yesterday';
    }
}

试试这个，我从我的旧代码中找到的，它显示了正确的结果

function ago($datefrom, $dateto = -1) {
    // Defaults and assume if 0 is passed in that
    // its an error rather than the epoch

    if ($datefrom == 0) {
        return "A long time ago";
    }
    if ($dateto == -1) {
        $dateto = time();
    }

    // Make the entered date into Unix timestamp from MySQL datetime field

    $datefrom = strtotime($datefrom);

    // Calculate the difference in seconds betweeen
    // the two timestamps

    $difference = $dateto - $datefrom;

    // Based on the interval, determine the
    // number of units between the two dates
    // From this point on, you would be hard
    // pushed telling the difference between
    // this function and DateDiff. If the $datediff
    // returned is 1, be sure to return the singular
    // of the unit, e.g. 'day' rather 'days'

    switch (true) {
        // If difference is less than 60 seconds,
        // seconds is a good interval of choice
        case(strtotime('-1 min', $dateto) < $datefrom):
            $datediff = $difference;
            $res = ($datediff == 1) ? $datediff . ' second' : $datediff . ' seconds';
            break;
        // If difference is between 60 seconds and
        // 60 minutes, minutes is a good interval
        case(strtotime('-1 hour', $dateto) < $datefrom):
            $datediff = floor($difference / 60);
            $res = ($datediff == 1) ? $datediff . ' minute' : $datediff . ' minutes';
            break;
        // If difference is between 1 hour and 24 hours
        // hours is a good interval
        case(strtotime('-1 day', $dateto) < $datefrom):
            $datediff = floor($difference / 60 / 60);
            $res = ($datediff == 1) ? $datediff . ' hour' : $datediff . ' hours';
            break;
        // If difference is between 1 day and 7 days
        // days is a good interval                
        case(strtotime('-1 week', $dateto) < $datefrom):
            $day_difference = 1;
            while (strtotime('-' . $day_difference . ' day', $dateto) >= $datefrom) {
                $day_difference++;
            }

            $datediff = $day_difference;
            $res = ($datediff == 1) ? 'yesterday' : $datediff . ' days';
            break;
        // If difference is between 1 week and 30 days
        // weeks is a good interval            
        case(strtotime('-1 month', $dateto) < $datefrom):
            $week_difference = 1;
            while (strtotime('-' . $week_difference . ' week', $dateto) >= $datefrom) {
                $week_difference++;
            }

            $datediff = $week_difference;
            $res = ($datediff == 1) ? 'last week' : $datediff . ' weeks';
            break;
        // If difference is between 30 days and 365 days
        // months is a good interval, again, the same thing
        // applies, if the 29th February happens to exist
        // between your 2 dates, the function will return
        // the 'incorrect' value for a day
        case(strtotime('-1 year', $dateto) < $datefrom):
            $months_difference = 1;
            while (strtotime('-' . $months_difference . ' month', $dateto) >= $datefrom) {
                $months_difference++;
            }

            $datediff = $months_difference;
            $res = ($datediff == 1) ? $datediff . ' month' : $datediff . ' months';

            break;
        // If difference is greater than or equal to 365
        // days, return year. This will be incorrect if
        // for example, you call the function on the 28th April
        // 2008 passing in 29th April 2007. It will return
        // 1 year ago when in actual fact (yawn!) not quite
        // a year has gone by
        case(strtotime('-1 year', $dateto) >= $datefrom):
            $year_difference = 1;
            while (strtotime('-' . $year_difference . ' year', $dateto) >= $datefrom) {
                $year_difference++;
            }

            $datediff = $year_difference;
            $res = ($datediff == 1) ? $datediff . ' year' : $datediff . ' years';
            break;
    }
    return $res;
}

示例:echo ago('2020-06-03 00:14:21 AM');

产出:6天

这里的许多解决方案没有考虑舍入。例如:

事件发生在两天前的下午3点。如果您在下午2点查看，它会显示在一天前。如果你在下午4点查看，它会显示两天前。

如果你使用unix时间，这有助于:

// how long since event has passed in seconds
$secs = time() - $time_ago;

// how many seconds in a day
$sec_per_day = 60*60*24;

// days elapsed
$days_elapsed = floor($secs / $sec_per_day);

// how many seconds passed today
$today_seconds = date('G')*3600 + date('i') * 60 + date('s');

// how many seconds passed in the final day calculation
$remain_seconds = $secs % $sec_per_day;

if($today_seconds < $remain_seconds)
{
    $days_elapsed++;
}

echo 'The event was '.$days_ago.' days ago.';

如果你担心闰秒和夏时制，这并不完美。

function time_elapsed_string($ptime)
{
    $etime = time() - $ptime;

    if ($etime < 1)
    {
        return '0 seconds';
    }

    $a = array( 365 * 24 * 60 * 60  =>  'year',
                 30 * 24 * 60 * 60  =>  'month',
                      24 * 60 * 60  =>  'day',
                           60 * 60  =>  'hour',
                                60  =>  'minute',
                                 1  =>  'second'
                );
    $a_plural = array( 'year'   => 'years',
                       'month'  => 'months',
                       'day'    => 'days',
                       'hour'   => 'hours',
                       'minute' => 'minutes',
                       'second' => 'seconds'
                );

    foreach ($a as $secs => $str)
    {
        $d = $etime / $secs;
        if ($d >= 1)
        {
            $r = round($d);
            return $r . ' ' . ($r > 1 ? $a_plural[$str] : $str) . ' ago';
        }
    }
}

再加上另一个选择……

虽然我更喜欢在这里发布的DateTime方法，但我不喜欢它显示0年等事实。

/* 
 * Returns a string stating how long ago this happened
 */

private function timeElapsedString($ptime){
    $diff = time() - $ptime;
    $calc_times = array();
    $timeleft   = array();

    // Prepare array, depending on the output we want to get.
    $calc_times[] = array('Year',   'Years',   31557600);
    $calc_times[] = array('Month',  'Months',  2592000);
    $calc_times[] = array('Day',    'Days',    86400);
    $calc_times[] = array('Hour',   'Hours',   3600);
    $calc_times[] = array('Minute', 'Minutes', 60);
    $calc_times[] = array('Second', 'Seconds', 1);

    foreach ($calc_times AS $timedata){
        list($time_sing, $time_plur, $offset) = $timedata;

        if ($diff >= $offset){
            $left = floor($diff / $offset);
            $diff -= ($left * $offset);
            $timeleft[] = "{$left} " . ($left == 1 ? $time_sing : $time_plur);
        }
    }

    return $timeleft ? (time() > $ptime ? null : '-') . implode(' ', $timeleft) : 0;
}