SQL Quiz Drills

■ No engine required. Run SELECT in your head.

SQLのエ is an iPhone app for practicing SQL in spare moments. Browser-based SQL playgrounds require sitting down at a PC; this app trades the engine for high-density questions, building real SQL skill through quick quizzes, repetition, and clear progress.

■ Who it's for
- New engineers who want SQL at their fingertips
- Analysts who need to read the SQL behind BI tools
- Anyone preparing for database/IT certification exams
- People who write SQL "by feel" and want to truly understand it

■ SQL-focused question formats
- Four-choice (fundamentals): quickly check syntax and terms
- Result-table prediction: guess the output from a table + query (our signature format)
- Fill-in-the-blank: memorize keywords
- True/False: check knowledge with rhythm

■ Learning modes
- Chapter training: basics through SELECT, WHERE, sorting, aggregates, GROUP BY, JOIN, subqueries, set operations
- Test: no explanations, just a score
- Oni (hard) training: 10 seconds per question, combos for streaks
- Daily 5: a fresh hand-picked set each day

■ Built to keep you going
- Streak (consecutive study days)
- Total queries solved and overall accuracy
- Per-chapter accuracy heatmap
- Achievement badges

■ Readable by design
- Dark theme with SQL syntax highlighting and monospaced font
- Clear result-table display

■ Privacy-first
- No account, no ads
- Works fully offline
- Learning data stays on your device (never sent out)

"10 questions a day. Run SELECT in your head." Make SQL a habit, starting today.

Note: The app does not execute real SQL. To try queries for real, use the external links (e.g., DB Fiddle) in Settings.