SQL practice online, free, on real data
Most SQL practice means typing answers to toy puzzles. SelectFromData is different: you write live SQL against real, messy datasets in your browser and get judged on whether you actually answered the business question. No install, no data leaves your machine, and you can start for free.
No card · in-browser · the SQL Fundamentals course and your entire first client (5 engagements) are free.
Free SQL practice online against real data, not flashcards
When people search for SQL practice online, they usually want two things: it should be free to start, and it should feel like the real thing instead of a quiz. SelectFromData gives you both. You query a real analytical database (DuckDB) running entirely in your browser, on datasets built to behave like exports you'd actually receive at work: an orders ledger that still has cancelled and returned rows mixed in, foreign keys that need joining, dates stored as text. The free tier includes the full SQL Fundamentals course and your entire first client (five Atlas Industrial engagements), so you can do a meaningful amount of real practice before deciding whether to pay for anything.
Because everything runs locally in the browser, there's nothing to install and nothing leaves your machine. You write a query, hit run, and see the result set the way you would in a real SQL client.
You learn by doing the job, not by answering trivia
Instead of disconnected exercises, each engagement drops you into a scenario as a data consultant for a recurring client, a bank, a manufacturer, an energy utility, a care network, a reinsurer. A stakeholder briefs you in plain language ('I need total revenue per sales channel for Q4 planning'), and you have to figure out the query yourself. The catch is the same one you hit in real work: the raw table lies. Quote revenue straight off it and you overstate the book by hundreds of thousands because cancelled and returned lines are still in there.
You can ask clarifying questions, get graded hints when you're stuck, and you're scored on the business outcome across four competencies, technical, insight, communication, and judgement, not on matching one 'correct' string. That's a closer rehearsal of the actual job than any multiple-choice drill.
A path from fundamentals to genuinely hard problems
If you're starting out, the SQL Fundamentals course teaches the building blocks with runnable SQL in every lesson, so you're executing queries from the first page, not just reading about them. From there a career ladder, Junior to Medior to Senior to Principal, unlocks progressively harder engagements as you deliver: filtering and joins early, then CTEs, window-style analysis, percentage-of-total within shifting denominators, dimensional modeling, and multi-round cases where one answer feeds the next.
Beyond SQL, there are structured courses in Python, Microsoft Fabric, and dimensional modeling. The aim is a real progression: from writing your first SELECT to handling the kind of ambiguous, dirty-data question a client would actually pay for.
Honest about where this is and isn't for you
SelectFromData is built by a practising data consultant, and it's early, pre-launch, with little traction yet. So there are no inflated learner counts or testimonials here to talk you into it. What's concrete is the product itself: a real in-browser database, real datasets with real traps, scenario-based grading, and a free tier you can fully judge for yourself.
It suits you best if you want practice that transfers to a job, analysts, aspiring data consultants, anyone preparing for SQL-heavy interviews or real client work. If you only want a quick syntax refresher, a flashcard app may be faster. If you want to practise the actual decisions analytics work demands, this is built for that.
Frequently asked
Is the SQL practice actually free?
Yes. The full SQL Fundamentals course and your entire first client — five consulting engagements — are free, with no payment required to start. Pro unlocks the remaining courses and engagements, but you can do substantial real practice on the free tier first.
Do I need to install anything or set up a database?
No. A real analytical database (DuckDB) runs entirely in your browser. There’s nothing to install, no server to connect to, and your queries and data never leave your machine.
Is this real SQL on real data, or just multiple choice?
It's real, live SQL. You write queries against realistic datasets, exports with cancelled orders, foreign keys to join, dates stored as text, and run them for actual results. You're graded on whether you answered the business question, not on picking a choice from a list.
What level is it for, beginner or experienced?
Both. Start with SQL Fundamentals if you’re new, with runnable SQL in every lesson. As you deliver, a Junior-to-Principal career ladder unlocks harder engagements covering CTEs, dimensional modeling, and ambiguous dirty-data problems closer to real consulting work.
How is my answer evaluated?
Each engagement checks your result against the business outcome the stakeholder asked for, across four competencies: technical, insight, communication, and judgement. You can ask clarifying questions and get hints, so being stuck is part of the learning rather than a dead end.
Learn it by doing it.
Deliver a real analysis in your browser in the next 30 minutes — free, no setup.