SQL Tester is an online practice and assessment tool for structured query language (SQL). Its code is available on GitHub. Students can answer the questions in any order and make as many attempts as they want within the set time limit (typically 50 minutes). The ten questions making up a practice test are drawn at random from a question bank. Only basic SQL is covered. Database schemas have at most three tables and are kept on display to help students avoid making naming errors in their queries. The desired output is also kept on display to help guide students. SQL Tester, however, does not provide feedback in addition to the error messages generated by the underlying relational database management system (here, MySQL).

The authors present an analysis of student engagement in practice tests and student performance on a final assessed test. Students spent an average of 4.25 hours on practice tests. The median score on the final assessed test was nine out of ten. The authors found a correlation between final test scores and the number of practice tests taken (r = 0.6). Average test scores increased with the number of practice tests taken. Questionnaire results were favorable.

The authors have constructed a tool that is usable and useful. However, they do not indicate whether the students also used tools such as MySQL Workbench or Oracle SQL Developer. These tools are powerful learning environments in their own right. This paper is recommended to database instructors only.