PHP stands for PHP: Hypertext Preprocessor. It is a server side technology like ASP. Unlike HTML, PHP needs server to run. You can freely download this software from the internet. It is open source software; you can easily customize this software according to your requirement.
My SQL is an ORACLE product and usually used in PHP and JAVA. It is used to store, update, delete and retrieve data. It is very powerful software and used in big and small application. It is a free software. MySQL is also used in large application including , Google and Facebook. MySQL is very flexible and its performance is very high.