PHP number of days miscalculation [duplicate] - php

Question

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How to calculate the difference between two dates using PHP?
(34 answers)
Closed 5 years ago.
I have this php code to calculate number of days between current date and specific date.
<?php
$query = mysql_query("SELECT * FROM library_users LEFT JOIN students ON library_users.student_id = students.student_id LEFT JOIN books ON library_users.book_id = books.book_id WHERE library_users.student_id <> ''")or die(mysql_error());
while($library_users = mysql_fetch_array($query))
{
$datefrom = date('d-m-Y');
$dateto = $library_users['return_date'];
$datefrom = DateTime::createFromFormat('d-m-Y', $datefrom);
$dateto = DateTime::createFromFormat('d-m-Y', $dateto);
$date_dur = $datefrom->diff($dateto);
$days = $date_dur->format('%d');
}
For now the current date is 27-06-2017; when I input tomorrow's date which is 28-06-2017 I'm getting 1 day which is fine, but when I input 27-07-2017(next month) it is giving me 0 days. How can I solve this?

Answer 1

The problem is that you are using the %d format to get the days, but this will give you the difference in days of a month.
Use %a instead:
$days = $date_dur->format('%a');
http://php.net/manual/en/dateinterval.format.php
a ==> Total number of days as a result of a DateTime::diff()

Answer 2

It works as designed.
DateTime::diff() returns an object of type DateInterval.
A DateInterval object stores the interval in years and subdivisions (months, days, hours, minutes and seconds). You tell it to format() itself using the format "%d".
The %d format specifier means the number of days; not the absolute number of days in the interval but only the days of the last incomplete month.
The format to display the total number of days is "%a":
$days = $date_dur->format('%a');

Answer 3

dumping your object between 27-06-2017 and 27-07-2017 give me this:
object(DateInterval)#4 (15) { ["y"]=> int(0) ["m"]=> int(1) ["d"]=> int(1) ["h"]=> int(0) ["i"]=> int(0) ["s"]=> int(0) ["weekday"]=> int(0) ["weekday_behavior"]=> int(0) ["first_last_day_of"]=> int(0) ["invert"]=> int(0) ["days"]=> int(31) ["special_type"]=> int(0) ["special_amount"]=> int(0) ["have_weekday_relative"]=> int(0) ["have_special_relative"]=> int(0) }
so your are right : it gives you 0 days but 1 month (["m"]=> int(1))
You must use:
$date_dur->days
to get the real days number.
regards.