Calculating time differences in PHP is sometimes a troublesome thing! But as long as you master the usage of date and time functions, it will become simple:
A simple example is to calculate the number of days to borrow a book. This requires PHP to calculate based on the date of each day. Let's talk about several methods to implement this date calculation:
(1) If you have a database, it will be easy! If you have MSSQL, you can use triggers! Just use the function datediff() that specially calculates the date difference!
If it is MYSQL, then the calculation result calculated using the difference between the two date fields is stored in another numeric field! Just call it when needed!
(2) If there is no database, you have to completely use PHP’s time and date function! The following is the main explanation:
Example: Calculate the number of days from May 3, 1998 to 1999-6-5:
<? $startdate=mktime("0","0","0","5","3","1998");
$enddate=mktime("0","0","0","6","5","1999");
//The obtained value is the total number of seconds from 1970-1-1 to the parameter time: it is an integer. Then
//The following code is much easier to write:
$days=round(($enddate-$startdate)/3600/24) ;
echo $days;
//days is the number of days obtained;
If the parameter in mktime() is defaulted, it means using the current date, so that the number of days from the date of borrowing the book can be calculated.
Don’t forget to return the book when it’s due! There will be a fine if it’s overdue!! @_@