claculating date with 2 variables

[Anon]

Need help on calculating date using 2 variables. I have 3 fields in my Mysql :
1) dateposted
2) duration
3) expire date

How can I calculate the expire date using original date (dateposted) and durations (eg 3 months)?

i'm using the following:
$exp_date = date("Y-m-d", mktime(0,0,0, date(m)+$delday, date(d),date(Y)));

It is only able to give me the expire date based on the current date.

[Anon]

Doesn't MySQL have functions itself to do this?

Anyway, you're halfway: use mktime to convert dateposted and duration into seconds, add them, and then convert the result back into a date.

[Anon]

I don't need the expire date to be in the database, as long as I am able to calculate the expire date using the start date and duration days, and have the expire date displayed.

I can't find anything that will help me to calculate date based on a date field stored in mysql. Almost all functions calculates from today.

[Anon]

You can still use MySQL's functions

SELECT [whatever the function for calculating the expiry date would be ] AS expiry_date FROM whatever...

Now, to just go over to MySQL's website and find some documentation...

Yep. Piece of proverbial. Less than a minute and I found a page with everything relevant on it:

http://www.mysql.org/documentation/mysql/bychapter/manual_Tutorial.html#Date_calculations