SQL stands for Structured Query Language. SQL is an international standard in querying and retrieving information from databases. MySQL is essentially an SQL server - it responds to requests for information that are written in SQL. You can communicate with MySQL using a wide variety of programming languages (PHP being one of the most common). MySQL is Open Source software and free for use.
Refer to the following link for more information about MySQL :
MySQL - The MySQL homepage.
MySQL and PHP tutorial - A good introduction to using the two Open Source technologies together.
To create a MySQL database:
Click on the MySQL databases button on the home page.
Enter the name of the database in the Db field.
Click on the Add Db button. The database will be added to the /var/lib/mysql folder.
You need to create at least one database user and grant that user permission to use the new database. Refer to Creating a MySQL user and Grant a user's permissions to a mysql database for more information.