Timestamp arithmetic

Anon

How do I take timestamp datatype from mysql and subtract 1 day and return that value? I want to do this with PHP not with MySQL

*************Example************
todays date with MySQL TIMESTAMP 20020804135649

I want to go back 1 day so the returned ariable would be

20020803135649

smook

You sure you don't want to do this with Mysql? You just name another column like this:

select mytimestamp,date_sub(mytimestamp, interval 1 Day) as Yesterday from mytable

The column will format a litte differently than a timestamp.

If you really must with php... and you don't want any help from mysql... do this -

parse out each element of the date:

$day = substr($myreturneddate,6,2);
$month = substr($myreturneddate,4,2);
$year = substr($myreturneddate,0,4);

then:

$yesterday = mktime(0,0,0,$month,$day-1,$year)

Note that the 0,0,0 are the hrs, minutes seconds which I didn't parse out.

The nice thing about the mktime is that if you have Feb 1, 2002 when you subtract 1 from the day it will be Feb 0,2002 and it knows that you mean Jan 31,2002..

You may want to put a date() around the mktime and format it to your given format... makes it prettier.