Date calculations... clear things up for me please.

[RoninStretch]

Ok, fairly noob at php so please bear with me..

 

I'm doin the old calculate persons age from database routine. Had a good search around and found out about Unix timestamps. Been looking those up and trying to figure out how to use them properly.

 

My dates are of the d-m-Y format.. I.E.. today is 11-02-2007

I did it this way so i can use date("d-m-Y") to grab todays date elsewhere in the site and it's all the same format.

 

Problem is that I can't quite grasp timestamps.

I tired something like this..

 

$dobts = strtotime($dateofbirth);
$todaysdate = date("d-m-Y");
$todaysdatets = strtotime($todaysdate);

$agets = $todaysdatets - $dobts;

$age = date("d-m-Y", $agets);

 

Didn't work of course but it thought that was the point of these timestamps?

 

Can anyone explain it better please?

[RoninStretch]

ok tried a bit more..

 

Had another look round and found a post or two that explained a little better.. but it's still not working.

 

here's the code now..

 

        $todaysdate = date("d-m-Y");

$diff = abs(strtotime($todaysdate) - strtotime($dateofbirth));
$day = 60 * 60 * 24; // seconds in a day
$agedays = $diff / $day; 
$age = floor($agedays/365);

 

but with $todaysdate = 22-05-1982

it chucks out 10... and should be 25.

I think maybe the strtotime doesn't like my date inputs?

 

Having a little read of the immense php manual tells me it takes a US date input.. so is that the problem?

if so it means re-writing alot of code or figuring a way to trick strtotime()..

 

So if this is the problem does anyone know a way of getting 22-05-1982 to 05-22-1982 before i use strtotime() on it?

 

any help appreciated.

[Barand]

Don't store dates as d-m-y , it's useless as a date format when storing in a db.

[RoninStretch]

ok well thanks for that... but what should i be doing?

 

Any help or links to reference, search terms... anything would help thanks.

[lightningstrike]

Save the data as a timestamp usually

 

//get timestamp in seconds and store in database
$timestamp = time();
//load timestamp from database then
//code to print date according to timestamp's value
$date = date("M-d-Y",$timestamp);

[RoninStretch]

Ok i will save dates as a timstamp then..

makes sense.

 

thanks guys will have to try that later tho.

[Barand]

I prefer DATE or DATETIME types

 

yyyy-mm-dd

or

yyyy-mm-dd hh:nn:ss

[RoninStretch]

Still having trouble with this..

Lots of trouble..  ???

 

Anyways.. so i have three list boxes for users to enter their date of birth.

Days, months and years.

 

I can change this to a timestamp now using strtotime. I think i'm doing it right..

$dateofbirth  = $dobyear . "-" . $dobmonth . "-" . $dobday;
$dobts = strtotime($dateofbirth);

 

now i store $dobts in my database..

 

Now the problem comes trying to display the persons age.

 

I grab the current timestamp-

$currentts = time();

 

then I'm guessing you subtract the date of birth from the current time.. leaving us with the amount of seconds since this person was born.

 

$agesecs = $currentts - $dobts;

 

then some trickery to make it into years... which im also kinda guessing at..

$age = $agesecs *60 *60 *24 *365;

 

but with the date of birth 22nd May 1982 this gives me the amazing out put of - 2.5112491353072E+16

 

so yeah... wrong..

 

please help, I don't have much hair left

 

 

 

 

[Barand]

You need to divide by seconds in a year, not multiply.

 

try

<?php
$dobts = mktime(0,0,0,5,22,1982);

$age = date('Y') - date('Y', $dobts);
if (date('md') < date('md', $dobts)) $age--;

echo $age;
?>