Not getting the required date - php

Question

I want to calculate the difference between date using date_diff(), whose 1st parameter is saved data in database and the 2nd parameter is today's date. The $pro_deadline is coming from database and is of type text (format yyyy-mm-dd), so I converted it into time using strtotime(). But in the end I'm getting "
Warning
: date_diff() expects parameter 1 to be DateTimeInterface, string given"
$today = date("Y-m-d");
echo $today;
$end = strtotime($pro_deadline);
$end_line = date("Y-m-d",$end);
echo $end_line;
$diff = date_diff($end_line,$today);
echo $diff;

Answer 1

as per PHP documentation http://php.net/manual/en/function.date-diff.php
date_diff — Alias of DateTime::diff()
so the perameters to date_diff should be DateTimeInterface types.
i would try
<?php
$today = date("Y-m-d");
echo $today." ";
$today = date_create($today);
$pro_deadline = '10-15-18';
$end = strtotime($pro_deadline);
$end_line = date_create(date("Y-m-d",$end));
$diff = date_diff($end_line,$today);
echo $diff->format('%a');
echo " days apart";
?>
the date_create() function is an alias of the DateTime constructor.
http://php.net/manual/en/datetime.construct.php
this creates an interface for the date/time that the date_diff() function can interpret. then date_diff() returns a DateInterval object
http://php.net/manual/en/class.dateinterval.php
the DateInterval object has a format method
http://php.net/manual/en/dateinterval.format.php
that can return the date in a sting for you.
Hope this explanation helps!

Answer 2

Like the error message says, date_diff expects DateTimeInterface parameters. strtotime returns a timestamp as an integer, which it can't work with.
Instead of creating timestamps, you can pass your deadline to the DateTime constructor, along with another version that'll default to now:
$today = new DateTime;
$end = new DateTime($pro_deadline);
and then pass these two objects to date_diff, and use the DateInterval::format method to display the number of days (assuming this is your desired output):
$diff = date_diff($today,$end);
echo $diff->format('%a');
See https://3v4l.org/QVkad for a full example

Answer 3

First of all, if you want a difference between a date in a database and today's date, just do it in the database directly. You didn't specify which DB, but, for example in MySQL you'd do something like:
SELECT DATEDIFF(some_field, now()) FROM ...
If you insist on doing it in PHP, then don't use strtotime but use DateTime object:
$today = new DateTime();
$end = new DateTime($pro_deadline);
$diff = $end.diff($today)

Answer 4

The date() function returns a simple string, but the date_diff() function expects a date object.
You can do it all much more simply with the functions in the DateTime class:
$pro_deadline = "2018-09-01";
$today = new DateTime();
$end = new DateTime($pro_deadline);
$interval = $end->diff($today);
echo $interval->format('%R%a days');
This example outputs +25 days Click here for Runnable Demo
Further examples of the diff() function here