比较PHP中的日期时的奇怪问题

Question

I am experiencing an issue when comparing two dates in php.

The problem: When comparing 12:00 AM (midnight) to eg 10:00 AM (morning) the following code will not work properly. According to human logic 10:00 AM is later than 12:00 AM. But computers seem not to recognize that.

Is there any way to do this differently?

date_default_timezone_set('Europe/Athens');
$today = date("d-m-Y h:i:s A");
$today = date("d-m-Y h:i:s A",strtotime($today));
$max = date('d-m-Y h:i:s A', strtotime("31-12-2015 23:59:00"));
$min = date('d-m-Y h:i:s A', strtotime("14-12-2015 00:00:01"));

if (($today > $min) && ($today < $max)){
    //do something
} else {
    //something else done
}

Answer 1

Because date() return String.

From the manual:

Return Values

Returns a formatted date string. If a non-numeric value is used for timestamp, FALSE is returned and an E_WARNING level error is emitted.

Basically, what your code trying to do is something like this:

if("31-12-2015 23:59:00 PM" < "14-12-2015 00:00:01 AM") {
    .......
}

So, PHP will ignore the "AM" or "PM" string, and just compare the numeric value.

EDIT: From comparison operator manual:

If you compare a number with a string or the comparison involves numerical strings, then each string is converted to a number and the comparison performed numerically.

So, because PHP convert their value again, then your code is comparing a different value entirely.

---

Is there any way to do this differently?

Just compare from the strtotime value.

$today = strtotime("now");
$max = strtotime("31-12-2015 23:59:00");
$min = strtotime("14-12-2015 00:00:01");

if (($today > $min) && ($today < $max)){
        //do something

}else{
        //something else done
}

and later format your value again using date to AM/PM format (if needed).