Relational Playground is an environment for students to explore the relationship between relational algebra expressions and SQL queries. This work is funded by a Provost’s Learning Innovation Grant (PLIG) from the Rochester Institute of Technology (RIT). The goal of this project is to help undergraduate and graduate students studying database systems to develop a deeper understanding of how queries are processed and optimized in relational database systems. The tool assists students with understanding connections between different representations of database queries and how formal representations are used as part of the query optimization process. The source for Relational Playground is available on GitHub.