DateTime（）计算两个日期之间的月数

Question

I'm using the below snippet of code which keeps returning 0 which isn't correct. $vtoday is the current date and the $pDate value is being checked against today to give a count of how many months have passed between the two dates.

Now I've tried strtotime() on both dates before being passed into DateTime() with no luck, I get an non-numeric error or something along those lines. I've also tried to format the two dates into 'Ymd' and then pass them into DateTime() with no luck either.

$vToday = date('Y-m-d H:i:s');
$pDate = '2013-03-11 12:13:03';

$vToday = new DateTime($vToday);
$vDate = new DateTime($pDate);
$vMonths = $vToday->diff($vDate)->m;

Am I going the completely wrong way to count the months between two dates or is there a simple problem with my logic?

Thanks for any help, tips or suggestions.

UPDATE:

Figured it out, answer below.

Answer 1

Value of m property of DateInterval class is always less than 12. If you want to get total number of months you have to add number of months multiplied by number of years:

$vToday = date('Y-m-d H:i:s');
$pDate = '2013-03-11 12:13:03';

$vToday = new DateTime($vToday);
$vDate = new DateTime($pDate);
$vDiff = $vToday->diff($vDate);
$vMonths = $vDiff->m + 12* $vDiff->y;

Answer 2

Figured it out, the way DateTime() works is that if say there is 12 months it wont return 12 it will return 0 as 12 months is one year so if you use the ->y option you will get 1 and ->m will output as zero.

$vToday = date('Y-m-d H:i:s');
$pDate = '2013-03-11 12:13:03';

$vToday = new DateTime($vToday);
$vDate = new DateTime($pDate);
$vDiff = $vToday->diff($vDate);
var_dump($vDiff);

If I remove the ->m option and output the object ($vDiff) below is what you will see, this is why I was getting zero for the month value.

object(DateInterval)#13 (15) { 
  ["y"]=> int(1) 
  ["m"]=> int(0) 
  ["d"]=> int(23) 
  ["h"]=> int(16) 
  ["i"]=> int(6) 
  ["s"]=> int(43) 
  ["weekday"]=> int(0) 
  ["weekday_behavior"]=> int(0) 
  ["first_last_day_of"]=> int(0) 
  ["invert"]=> int(1) 
  ["days"]=> int(388)
  ["special_type"]=> int(0) 
  ["special_amount"]=> int(0) 
  ["have_weekday_relative"]=> int(0) 
  ["have_special_relative"]=> int(0) 
} 

Answer 3

you should use

$current_month = date('M');

It will return the current month. and if you do date('Y') it will return the corresponding year.

1. Find the difference between two months

2. Check if the difference between the years is greater than 1, if so then add 12 to the month difference you found in step 1.

Answer 4

Try this:-

$vToday = date('Y-m-d H:i:s');    
$pDate = '2013-03-11 12:13:03';    
$vToday = new DateTime($vToday);
$vDate = new DateTime($pDate);
$vDiff = $vToday->diff($vDate);
$vMonths = $vDiff->m + 12* $vDiff->y;
echo "Difference - ".$vMonths;