php check for a valid date, weird date conversions

Question

Is there a way to check to see if a date/time is valid you would think these would be easy to check:

$date = \'0000-00-00\';
$time = \'00:00:00\';
$dateTime          


        

Answer 1

echo date('Y-m-d', strtotime($date));

results in: "1999-11-30"

The result of strtotime is 943920000 - this is the number of seconds, roughly, between the Unix epoch (base from which time is measured) to 1999-11-30.

There is a documented mysql bug on mktime(), localtime(), strtotime() all returning this odd value when you try a pre-epoch time (including "0000-00-00 00:00:00"). There's some debate on the linked thread as to whether this is actually a bug:

Since the time stamp is started from 1970, I don't think it supposed to work in anyways.

Below is a function that I use for converting dateTimes such as the above to a timestamp for comparisons, etc, which may be of some use to you, for dates beyond "0000-00-00 00:00:00"

/**
 * Converts strings of the format "YYYY-MM-DD HH:MM:SS" into php dates
 */
function convert_date_string($date_string)
{
    list($date, $time) = explode(" ", $date_string);
    list($hours, $minutes, $seconds) = explode(":", $time);
    list($year, $month, $day) = explode("-", $date);
    return mktime($hours, $minutes, $seconds, $month, $day, $year);
}