This book starts with the concepts in RDBMS (Relational Database Management Systems) and SQL (Structured Query Language). The first few chapters cover the definitions and a brief explanation of all the important concepts. They also cover the installation of MariaDB and MySQL on Windows and Raspberry Pi, as well as the setup of various tools used to connect to MySQL and MariaDB server processes. We will also understand how to install sample schemas and how to use basic SQL queries. Then we move on to the SELECT query in detail. The book explores the data retrieval aspect of SQL queries in detail with the WHERE clause and NULL handling in detail. The book also explores the functions available in MySQL. Those are single row and group functions. Then we explore how to combine the data from multiple sources. The technique is known as Joins, and we will learn ANSI style and the old-style syntax for all the types of Joins.The last part explores the DDL and DMLs in depth. We also learn the concepts of Transactions and Constraints. The book explores how we can run the SQL queries from a Python 3 program and load a pandas DataFrame with the data from a table in a schema in the MySQL database.