One of the most popular ways to create a modern database-driven web site is to store the content in a MySQL database. You can then retrieve the information, and search the database, using MySQL commands.
If you've read about MySQL but never used it, and you fancy teaching yourself the basics, there are lots of free online resources that you can start with. But at some point you'll also want access to a working system that you can use to test out your skills and to experiment.
One place where you can find such a facility is at http://headfirstlabs.com/sql_hands_on/. It's free to use, and can be accessed via your web browser. There's a series of database tables, all set up with some sample data, and a set of pre-assembled queries that you can run. Once you've run a query and you reckon you understand how it works, you can then tweak the query slightly and run it again, and examine the results to see if they're what you expected.
If you want to learn basic MySQL, and you want a simple sandbox in which to practice your skills, this is the perfect place.