Sharpen SQL.
Take the offer.
700+ problems — from the basics to real interview questions asked at Google, Meta and Amazon. AI finds your weak spots and hammers them with fresh problems.
This is the Beast of Query. Every player gets one — and it evolves with every new rank.
questions from real interviews
- Meta
- Amazon
- Microsoft
- Tesla
- Spotify
Same question. Three dialects.
PostgreSQL, MySQL and ClickHouse — practice on whatever your interview uses.
SELECT city, sum(amount) AS revenue FROM orders WHERE created_at >= now() - INTERVAL 30 DAY GROUP BY city ORDER BY revenue DESC LIMIT 3 SETTINGS max_threads = 4;
ClickHouse: lower-case functions, and SETTINGS controls execution.
| city | revenue |
|---|---|
| Москва | 4 812 304 |
| Санкт-Петербург | 2 117 880 |
| Казань | 934 215 |
From task to verdict in 3 minutes
No onboarding. Open it, write it, see where you blew it — back into the ring.
Pick a task
Topic, level, company — filters in one click.
Write SQL
Write the query right in the browser — PostgreSQL, MySQL or ClickHouse. Monaco editor with syntax highlighting and autocomplete.
Get the verdict
Diff against canonical. AI pinpoints the mistake.
Learn what they'll ask. Not what's in the textbook.
Analyst, backend, QA, data engineer — each role has its own set. Plus a dedicated interview-prep track.
Analyst
So your PM stops asking 'do you know SQL?'
- JOINs, aggregates, GROUP BY
- Window functions
- CTEs and nested subqueries
Backend
So your lead stops catching your N+1 in prod
- INSERT / UPDATE / DELETE and transactions
- Optimisation and EXPLAIN
- Complex subqueries and CTEs
QA / Testing
To test the data, not just UI clicks
- SELECT-based checks and filters
- Aggregates: counts, dups, anomalies
- DML for fixture setup
Data Engineering
To build data marts, not paste SELECT *
- DDL: schemas, tables, constraints
- Window functions and aggregates
- CTEs and complex transforms
AI builds a task on the exact thing you missed yesterday
Struggling with window functions? Five fresh cases land in your queue until they stick.
- Targets weak spotsLooks at your last 40 submissions and picks the topic you keep missing right now.
- Schema fits the caseEvery generated task ships with a schema and seed data built for that exact scenario.
- Auto-gradedDiff against canonical on hidden seed. No reviewer queue.
- Tracks your levelOn a streak? Difficulty climbs. Stalling? The next one drops a notch.
$ ai.generate(adaptive=true)
No second chances in a real interview. Here, take as many as you need.
Timer runs on the server, browser is locked, no hints.
A certificate you can verify
Pass the timed exam and earn a level certificate with QR verification. Three levels: Foundations, Practitioner, Expert.
Eight ranks, Junior to Titan.
Hit Senior and interviews stop scaring you.
Every solve earns power. Streaks, achievements, weekly leaderboard. Your closest rivals are always in sight.
Harder task × first try × interview mode = faster rank. Premium solves grant ×1.5 Power — the boost is permanent.
- EASY · 10 power
- MEDIUM · 25 power
- HARD · 50 power
- EXPERT · 75 power
Challenge a live opponent. One problem — one winner.
PvP duels: one problem, two beasts, a shared timer. Winner takes the Power.
Free — forever. Premium — when you want more.
No auto-charges: pay for a period, train. The longer the period, the cheaper each month.
- Every Easy-level task — interview easies included
- Your own 3D query beast from the first task
- Sandbox and all three dialects
- Leaderboard, streaks and achievements
- All Medium, Hard and Expert tasks — interview questions included
- Unlimited AI mentor and problem generation
- Unlimited Interview mode and certificates
- +50% Power for every solve — permanently
The short version
Is it free?
Yes. Every Easy-level task — including easy questions from real interviews — plus ranks, your beast, the sandbox and the leaderboard: free forever, no card. Premium unlocks the harder tiers (Medium, Hard, Expert), unlimited AI and Interview mode.
Which SQL dialects are supported?
PostgreSQL, MySQL and ClickHouse — we're the only trainer with ClickHouse problems. Your solution runs on a real database and is graded instantly.
Is it good for interview preparation?
Yes. There's an Interview mode with a timer and focus tracking — like a real tech screen — plus problems from Google, Meta, Microsoft, Tesla and other companies' interviews.
What is AI problem generation?
The AI creates unique SQL problems for your level and chosen topics (JOIN, subqueries, window functions) with a ready dataset and a reference solution — and it sees where you fail most.
Do I need a card? Is there auto-renewal?
Free needs no card at all. Premium is a one-time payment per period (from $4.7/mo) — no auto-renewal, nothing charged behind your back.
The axe is in your hand. Swing.
Two minutes to your first task. One month to the offer. Your move.
Claim your rankBack to training