The set of commands we'll use to tell MySQL what to do for the rest of this book is part of a standard called Structured Query Language, or SQL (pronounced either "sequel" or "ess-cue-ell" — take your pick). Commands in SQL are also called queries (I'll use these two terms interchangeably in this book).
SQL is the standard language for interacting with most databases, so even if you move from MySQL to a database like Microsoft SQL Server in the future, you'll find that most of the commands are identical. It's important that you understand the distinction between SQL and MySQL. MySQL is the database server software that you're using. SQL is the language that you use to interact with that database.