Hello this is very simply lol
Put all the sql queries required by the application to get relevant data in a single file or folder and you have an API centric php module. The application prefarably a mobile app or software application processes the queries and obtains necessary information to display at the front-end. Long story short, do not build the entire application using PHP. Just use PHP for backend
It is used to tell the sever to use the PHP parser. To begin php you must use <?php, and to end it, it is ?>.
You can't use PHP in an HTML document, but you can use HTML in PHP script.
In Core-PHP I would assume both are difficult. But between the two Amazon clone would be a bit harder. Ideal thing would be to use Magento to create an Amazon type site.
PHP files extension is .php
Firstly, this is wrong question. The right one would be WHEN should you use PHP, not JSP? or, WHEN should you use PHP and WHEN JSP?
PHP 5 has a XML parser called SimpleXML that you could use.
You can use phpMailer() Or, you can use mail() PHP function to send emails via PHP script.
PHP certification is received after doing some sort of PHP course, there are many out there to do. You can use them in your CV to help you get a job in PHP.
Facebook uses PHP 5.
There are no PHP tags. Unlike HTML, PHP is not Markup language. They use scripts. An example would be <?php echo "Hello, World!"; ?>
That's PHP Engine.. Allow you to develop PHP Scripts.. you can use it to develop PHP Scripts and test it on your local machine before you send it to server.. (your website)