PHP中两个日期之间的差异

Question

I am trying to get the difference between two months. For instance for below, I would want 2 months.

$datetime1 = date_create('2017-03-01');
$datetime2 = date_create('2017-04-30');
$interval = date_diff($datetime1, $datetime2);
echo $interval->format('%m months');
echo $interval->format('%d days');

This gives me 2 months and 1 day.

Answer 1

The reason why you're getting an incorrect result is most likely because you haven't set a default timezone, one for "your" timezone.

• http://php.net/manual/en/function.date-default-timezone-set.php

In adding and for example:

date_default_timezone_set('America/New_York');

returned the correct time difference, while not using it returned what you are presently getting.

Use the one for your own timezone, or set it in your system file(s).

From the manual http://php.net/manual/en/datetime.diff.php under "User Contributed Notes":

"When using datediff make sure your time zone is correct, for me on Windows 7 64 bit it behaved very strange when timezone was wrong (I was comparing now against time in database and exif metadata in photos). For example: date_default_timezone_set('Europe/Oslo');"

and go through the rest of "User Contributed Notes".

• Another possible reason would be the server's location which is different from "your" position on "earth".

Relevant link from comments given by RiggsFolly:

• php date and daylight savings time confusion

which could be at play here.

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Edit:

After noticing the OP accepting this answer, taken from a comment by RiggsFolly was to also add:

date_default_timezone_set('UTC');

I would call this a joint venture and I can't take full credit for this.