Abstract
While SQL has a relatively simple syntax with a small set of commands, it allows for complex query construction that is deceptively challenging. SQL is often the first declarative programming language learned by students, which requires a different analysis approach than that used to understand the procedural or object-oriented programming paradigms with which students are more familiar. While some tools exist to help assess the correctness of an SQL query or address syntax errors, few tools focus on query semantics. DBQA does so by illustrating the effects that clauses and conditions have on an SQL SELECT statement using a visualized, data-oriented approach. We expect DBQA's approach to query evaluation to feel more familiar to those with experience in procedural or object-oriented programming and to help those users better understand the semantics of complex queries. DBQA includes support for SQL queries containing JOINs and subqueries, which have been shown to be among the most difficult for students to construct.