如何从MySQL时间戳数据类型的日期中减去一天？

Question

In my Worpdress site I am using the function current time to return the current date in MySQL timestamp data type format.

My goal is to perfom some operations on the result (like substracting 1 day). I found on the web date_sub but the requirement is that its parameter should be a DateTime type.

Warning: date_sub() expects parameter 1 to be DateTime, string given in C:\\xampp\\htdocs\\blog\\wp-content\\themes\\twentyten\\header.php on line 107

How can I perform substraction on the MySQL timestamp data type format, or is there a Worpdress function that returns current date in DataTime format?

You help is always appreciated.

Answer 1

PHP date function can return date in whatever format you want.

$datetime = date('Y-m-d H:i:s', time() - (1 * 86400));

This will generate curent time in unix and take one day out. If fed as second param to date function it will be converted in that format.

$a_day_ago = time() - (1 * 86400);

http://php.net/manual/en/function.date.php

If you wish to do it directly in MySQL.

Date and time:

NOW() - INTERVAL 1 DAY

Just date:

CURDATE() - INTERVAL 1 DAY

Answer 2

I think is what you are looking for:

<?php
function longdate($timestamp)
{
return date("l F jS Y", $timestamp);
}
?>

If you need to print out the date 17 days ago, you now just have to issue the following call:

echo longdate(time() - 17 * 24 * 60 * 60);

which passes to longdate the current Unix timestamp less the number of seconds since 17 days ago (17 days × 24 hours × 60 minutes × 60 seconds).

Answer 3

Something like this should work:

$date = new DateTime();
$date->sub(new DateInterval("P1D"));
echo $date->format("Y-m-d H:i:s");

If you aren't familiar with it, you should look at PHP SPL Date/Time classes. They are immensely useful and make this type of thing very easy.