WordPress is an open-source and widely used content management system that is based on PHP and MySQL. It is the most popular blogging platform, which powers over 20% of the overall website currently active on the world wide web.
WordPress requires MySQL to store and retrieve all of its data including post content, user profiles, and custom post types. Most web hosting providers already have MySQL installed on their web servers as it is widely used in many open source web applications such as WordPress.
WordPress uses the PHP programming language to store and retrieve data from the MySQL database. To retrieve data from the database, WordPress runs SQL queries to dynamically generate content. SQL stands for Structured Query Language and is the programming language typically used to query databases.