DateTime compare two dates - php

Question

The goal is to diff two dates.
I have a DateTime object stored in my db table under timestamp column. I use Doctrine to retrieve the date, Once retrieved the date from my db it looked like this by var_dump;
array(1) {
[0]=>
array(1) {
["timestamp"]=>
object(DateTime)#321 (3) {
["date"]=>
string(26) "2016-08-03 11:03:36.000000"
["timezone_type"]=>
int(3)
["timezone"]=>
string(13) "Europe/London"
}
}
}
the retrieved object was assigned to a $result variable now to get to the DateTime object I did this $result[0][timestamp].
To retrieve the actual data i did this $date1 = $result->format('Y-m-d H:i:s'); according to this documentation
So now that i have retrieved the date a row was inserted into my db I need another date as of current time.
i.e:
$date1 = $result->format('Y-m-d H:i:s');
$date2 = new DateTime();
$test = $date1->diff($date2);
diff according to this documentation
this gives me this error:
Error: Call to a member function diff() on a non-object
Any idea why i get this error message looks like am doing things the right way according to the docks. Maybe there is another way do diff two dates OPP way.
UPDATE:
Ok so yes it is true if I use $date1 = $result->format('Y-m-d H:i:s'); its no longer a object its a stiring.
So now my code looks like this:
$test = $result->diff(new DateTime());
var_dump($test);
it returns DateInterval object but what do i make out of it:
object(DateInterval)#317 (15) {
["y"]=>
int(0)
["m"]=>
int(0)
["d"]=>
int(0)
["h"]=>
int(1)
["i"]=>
int(27)
["s"]=>
int(5)
["weekday"]=>
int(0)
["weekday_behavior"]=>
int(0)
["first_last_day_of"]=>
int(0)
["invert"]=>
int(0)
["days"]=>
int(0)
["special_type"]=>
int(0)
["special_amount"]=>
int(0)
What i need if Date1 diff to Date2 is > than 30 mins I want to take some actions.

Answer 1

It is because method format returns string, but not object. Try to use:
$test = $result->diff(new DateTime());

Answer 2

$date1 = $result->format('Y-m-d H:i:s');
$date1 is now a string which doesn't have a format() method.
Try this instead:-
$date1 = $result->format('Y-m-d H:i:s');
$date2 = new DateTime();
$test = $result->diff($date2);

Answer 3

After you do $date1 = $result->format('Y-m-d H:i:s');. $date1 is no more a DateTime object, rather a string representation of date and time.
Hence skip this line. Don't format, and then check for difference. That will give you a DateTimeInterval object.

Answer 4

For anyone who doesn't know what diff() does, it compares two dates and returns the difference -- but unlikely other subtraction methods, diff() never returns a negative value. It doesn't matter if the first date is larger or smaller than the second date.
Now, if that is not a concern for this case, the next step is to access the necessary values in the DateInterval object.
$diff=(array)$date1->diff($date2); // calculate the difference and cast as an array
$labels=array("y"=>"year","m"=>"month","d"=>"day","h"=>"hour","i"=>"minute");
// filter the $diff array to only include the desired elements and loop
foreach(array_intersect_key($diff,$labels) as $k=>$v){
if(($k!="i" && $v>0) || $v>30){
// $labels[$k] = $v > 30 minutes, take some action
}
}