Level up your SQL skills
Interview tasks, unlimited AI mentor and AI-generated practice for your level
Free
For learning SQL basics
All basic tasks and AI hints
No card
- 234 Easy-level tasks
- PostgreSQL, MySQL, ClickHouse, BigQuery
- Instant grading
- AI hints and explanations — 10 total
- EXPLAIN — query plan analysis
- Mock Interview mode — 1 attempt / day
- Power, streak, achievements, leaderboard
- ER schema diagrams
Premium
The trainer, without the courses
≈ $7.83/mo — save 35%
One-time payment, no auto-renewal
Visa, Mastercard, Amex via Paddle.
- Everything in Free
- +50% Power per solved task — the boost locks in forever, even after the subscription expires
- Unlimited Mock Interview attempts, up to +50% Power per clear (scales with your chosen rules)
- 1-on-1 duels: live SQL matches against real opponents, custom arenas and Power stakes
- Every hard interview problem — Medium, Hard and Expert (Google, Meta, Tesla…)
- Unlimited AI hints and error explanations
- AI-generated tasks for your level — up to 10 / day
- Community top solutions
- Timed certification exam — a verifiable certificate for every level
Pro
The trainer and all the courses
≈ $9.83/mo — save 34%
One-time payment, no auto-renewal
Visa, Mastercard, Amex via Paddle.
- Everything in Premium
- SQL Course — 12 modules, 77 lessons: from the first SELECT to window functions, a capstone project and a path to the certificate
- Data Analysis Course — 13 chapters, 83 lessons: Python and pandas in the browser, product metrics, cohorts, A/B tests and eleven investigations
- SQL Performance course — 10 chapters, 49 lessons: EXPLAIN ANALYZE, the four scan types, indexes and sargability, JOIN algorithms, work_mem and planner statistics
- BigQuery course — 8 chapters, 27 lessons: arrays and STRUCTs, windows with QUALIFY, shards and wildcard tables, and the bill for bytes read
- Data Engineering course — 10 chapters, 58 lessons: intake and high-water marks, a star-schema warehouse with SCD2, Airflow 3 DAGs, ClickHouse and MergeTree, backfills, data-quality checks and Kafka
- ClickHouse course — 8 chapters, 41 lessons: aggregate combinators, arrays as columns, funnels and retention, time without gaps, joins, and the layout that sets the price of an answer
Pro includes everything in Premium and adds every course on the platform
What the subscription gives you
+50% Power per solve
Boost locks in forever — stays after subscription ends
Courses, not just the trainer
Courses on SQL, Data Analysis, SQL Performance and BigQuery — Python, pandas and statistics right in the browser. All of them open in full on the Pro plan.
Unlimited Mock Interview
Removes the “1 attempt per day” cap, plus up to +50% bonus Power per clean pass
Hard interview problems
Medium, Hard and Expert from Google, Meta, Tesla and others — the easy ones are free too
Unlimited AI mentor
Hints and error explanations with no limit
AI-generated tasks
Up to 10 unique tasks per day for your level
1-on-1 duels
Live SQL matches against real opponents, custom arenas and Power stakes
Certification exam
A timed exam and a verifiable certificate for every level
Top community solutions
Learn from the best — see how others solve