What to Expect and What to Focus on in SQL Query Teaching

In the process of learning a new computer language, writing erroneous statements is part of the learning experience. However, some errors persist throughout the query writing process and are never corrected. Structured Query Language (SQL) consists of a number of different concepts such as expressions, joins, grouping and ordering, all of which by nature invite different possible errors in the query writing process. Furthermore, some of these errors are relatively easy for a student to fix when compared to others. Using a data set from three student cohorts with the total of 744 students, we set out to explore which types of errors are persistent, i.e., more likely to be left uncorrected by the students. Additionally, based on the results, we contemplate which types of errors different query concepts seem to invite. The results show that syntax and semantic errors are less likely to persist than logical errors and complications. We expect that the results will help us understand which kind of errors students struggle with, and e.g., help teachers generate or choose more appropriate data for students to use when learning SQL.