PHP : How to get milisecond between two dateTime obj?

Question

PHP : How to get milisecond between two dateTime obj? $date = new DateTime(); $date2 = new DateTime("1990-08-07 08:44");

I try to follow the comment below but I got an error $stime = new DateTime($startTime->format("d-m-Y H:i:s")); $etime = new DateTime($endTime->format("d-m-Y H:i:s")); $millisec = $etime->getTimestamp() - $stime->getTimestamp();

I get an error "Call to undefined method DateTime::getTimestamp()"

Answer 1

DateTime dates are only stored as whole seconds. If you still need the number of milliseconds between two DateTime dates, then you can use getTimestamp() to get each time in seconds (then get the difference and turn it into milliseconds):

$seconds_diff = $date2.getTimestamp() - $date.getTimestamp()
$milliseconds_diff = $seconds_diff * 1000

Answer 2

In the strict sense, you can't.

It's because the smallest unit of time for the DateTime class is a second.

If you need a measurement containing milliseconds then use microtime()

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Edit:

On the other hand if you simply want to get the interval in milliseconds between two ISO-8601 datetimes then one possible solution would be

function millisecsBetween($dateOne, $dateTwo, $abs = true) {
    $func = $abs ? 'abs' : 'intval';
    return $func(strtotime($dateOne) - strtotime($dateTwo)) * 1000;
}

Beware that by default the above function returns absolute difference. If you want to know whether the first date is earlier or not then set the third argument to false.

// Outputs 60000
echo millisecsBetween("2010-10-26 20:30", "2010-10-26 20:31");

// Outputs -60000 indicating that the first argument is an earlier date
echo millisecsBetween("2010-10-26 20:30", "2010-10-26 20:31", false);

On systems where the size of time datatype is 32 bits, such as Windows7 or earlier, millisecsBetween is only good for dates between 1970-01-01 00:00:00 and 2038-01-19 03:14:07 (see Year 2038 problem).