Log every practice question, see which topics need work, and come back to each one when it is due.
An Excel workbook for SQL interview practice. The Log takes one row per attempt: date, topic, question, minutes, solved or not, how sure you felt (1 to 5) and the kind of mistake. Each question gets its own review date from your latest attempt at it: the next day if you did not solve it, up to 30 days if you solved it and could explain it. The Topics sheet shows attempts, solved rate, average confidence and time for each of 14 topics, the earliest review among its questions, and how many are due.
A bank of 30 practice questions comes with it, on the datasets of the LucidPlexus books: HealSync's claims and sessions, Clearstone's books, Lanternfield's startups, the agricultural data and Verdant Union's emissions, from Easy to Hard. Every question was checked against the data, and many hide a trap the data really contains: a duplicated key, a NULL, a tie, a join that multiplies rows.
The answers are on their own sheet: a DuckDB query, the result it printed, and what to watch for. Try first, then check.
XLSX for Excel 2019 or Microsoft 365, or LibreOffice (it uses MAXIFS and MINIFS, which older Excel lacks), 6 sheets. Formulas only, no macros.