arithmetics with timestamp?

[Super Mango]

Hi everubody,

I have a timestamp field in a mysql DB and I want to know how much time
has past since that timestamp.

is it possible?
Say that I have this value in a variable -
1) how do I get the current system timestamp?
2) how do I subtract the first from the second?

Thanks!

[Janwillem Borleffs]

Re: arithmetics with timestamp?

Super Mango wrote:[color=blue]
> Say that I have this value in a variable -
> 1) how do I get the current system timestamp?
> 2) how do I subtract the first from the second?
>[/color]

If you are only interested in the amount of hours, you could do something
like:

$now = time();
$past = time() - 86400;

print 'The difference between $past and $now = ';
echo ($now - $past) / 3600, ' hours';

Of course, you can narrow this figure down to days (div 86400), hours (div
3600), minutes (div 60) and seconds.

These kind of calculations can also be performed by MySQL. Have a look at
the manual @ mysql.com for more info.


JW

[Super Mango]

Re: arithmetics with timestamp?

thanks!

But the thing is that the value in the DB is kept as YYYY-MM-DD hh:mm
how do I convert that to the "time()" format?

[Dave Kelly]

Re: arithmetics with timestamp?

Super Mango wrote:[color=blue]
> Hi everubody,
>
> I have a timestamp field in a mysql DB and I want to know how much time
> has past since that timestamp.
>
> is it possible?
> Say that I have this value in a variable -
> 1) how do I get the current system timestamp?
> 2) how do I subtract the first from the second?
>
> Thanks!
>[/color]
I can show you how to do it at a website down the wire using a bash
script. Should be adaptable to something local and PHP.

TIMESTAMP=$(dat e -d "`lynx -error_file=lynx _error -dump
-connect_timeout =20 $url/timestamp.txt`" +%s)

[Janwillem Borleffs]

Re: arithmetics with timestamp?

Super Mango wrote:[color=blue]
> thanks!
>
> But the thing is that the value in the DB is kept as YYYY-MM-DD hh:mm
> how do I convert that to the "time()" format?
>[/color]

Per example, with strtotime: http://www.php.net/strtotime

JW

[Gordon Burditt]

Re: arithmetics with timestamp?

>I have a timestamp field in a mysql DB and I want to know how much time[color=blue]
>has past since that timestamp.
>
>is it possible?[/color]

Yes. Use MySQL to do it.
[color=blue]
>Say that I have this value in a variable -
>1) how do I get the current system timestamp?[/color]

now()
[color=blue]
>2) how do I subtract the first from the second?[/color]

timestampdiff() . (requires MySQL 5.0 or greater).
timediff(), but it returns the value in hours, minutes, and seconds.
datediff(), but only the date parts are used.

Gordon L. Burditt

[Pedro Graca]

Re: arithmetics with timestamp?

Super Mango wrote:[color=blue]
> But the thing is that the value in the DB is kept as YYYY-MM-DD hh:mm
> how do I convert that to the "time()" format?[/color]

select UNIX_TIMESTAMP( column) from table;

--
Mail to my "From:" address is readable by all at http://www.dodgeit.com/
== ** ## !! ------------------------------------------------ !! ## ** ==
TEXT-ONLY mail to the whole "Reply-To:" address ("My Name" <my@address>)
may bypass my spam filter. If it does, I may reply from another address!

[Toby Inkster]

Re: arithmetics with timestamp?

Super Mango wrote:
[color=blue]
> I have a timestamp field in a mysql DB and I want to know how much time
> has past since that timestamp.[/color]

<?php
// Assume timestamp from database is in $ts.
$then = strtotime($ts);
$now = time();
$diff = $now - $then;
// $diff is the difference in seconds.
?>

--
Toby A Inkster BSc (Hons) ARCS
Contact Me ~ http://tobyinkster.co.uk/contact

[d]

Re: arithmetics with timestamp?

"Super Mango" <liebermann@gma il.com> wrote in message
news:1137344888 .413098.327320@ o13g2000cwo.goo glegroups.com.. .[color=blue]
> Hi everubody,
>
> I have a timestamp field in a mysql DB and I want to know how much time
> has past since that timestamp.
>
> is it possible?
> Say that I have this value in a variable -
> 1) how do I get the current system timestamp?
> 2) how do I subtract the first from the second?
>
> Thanks![/color]

If you're going to be doing the vast majority of your time maths outside
MySQL, you might want to use integers instead of timestamps - you can just
save the unix timestamp in the database, which saves time converting between
MySQL and unix times. And, of course, you can still search/sort using the
unix timestamp...