SQL Practice vs ChairBack

Learn SQL in 15-minute daily sessions — on your phone, anywhere. SQL Practice turns idle moments into practical data skills. With interactive exercises, realistic datasets, and instant feedback, you’ll build SQL confidence from beginner fundamentals to interview-ready skills. Who it’s for: - Career changers entering tech - Professionals adding SQL to their toolkit - Students preparing for technical interviews - Anyone curious about data and databases Why it’s different: - Learn by doing: write and run real SQL queries - SQL Patterns (Pro): understand reusable approaches instead of memorizing answers - Database Bits (Pro): build intuition with short, visual lessons - Smarter feedback (Pro): see why your result differs from the expected output - Progressive curriculum: start with the fundamentals and advance at your own pace - Mobile-first design: practice whenever you have a few spare minutes When you get stuck: With Pro, SQL Practice helps you move forward without immediately giving away the answer. Use progressive hints, compare your results with the expected output, and explore SQL X-Ray explanations that break queries into understandable steps. What you’ll learn: - SELECT, WHERE, ORDER BY, and filtering - JOINs and relationships between tables - COUNT, SUM, AVG, GROUP BY, and HAVING - Subqueries and advanced query techniques - Reusable SQL patterns (Pro) - Core database concepts, indexes, and data design (Pro) Practice your way: - Guided SQL lessons - Easy, medium, and hard exercises - Quick drills - Short visual database lessons (Pro) - Daily practice challenges - Streaks, XP, achievements, and progress tracking - Hardcore mode: turn off the advanced SQL keyboard and solve the toughest challenges without assistance—the highest level of SQL practice. Free and Pro: Core SQL lessons, exercises, drills, streaks, and basic progress tracking are free. An optional auto-renewing Pro subscription unlocks SQL Patterns, Database Bits, progressive hints, detailed result comparisons, and SQL X-Ray step-by-step explanations. Available plans, billing periods, trial eligibility, and localized prices are shown before purchase. No purchase is required to use the core learning and practice features. Start your data journey today — no prior coding experience required, just 15 minutes of curiosity. Privacy Policy: https://martongreber.github.io/mvp/privacy.html Terms of Use: https://martongreber.github.io/mvp/terms.html

ChairBack is the app for the chair - for the barber running it, and the client sitting in it. If you cut hair, your whole book lives on your phone. See your day hour by hour or your month at a glance, and take a booking, move one, or block off time in a couple of taps. When the cut is done, check your client out right there at the chair and record what you actually collected, whether that was cash, card, or transfer. A walk-in takes one tap: no name, no signup, just what they paid. Between clients you can see who is coming in next, who has not been back in a while, how full your chair really is, and what your time is honestly worth. Already booked somewhere else? Bring your book with you from Acuity or Square, or import a client list, and keep the appointments you already have. If you are the one in the chair, there is nothing to sign up for. Find your shop by its exact name, or open the link your barber sent you, and your rewards card is waiting - your visits, the tier you are on, and how close the next one is. Book your next cut in a few taps, or set a standing appointment so your usual time stays yours for the weeks ahead. A reminder lands before you are due so you never lose the slot, and your card can live in Apple Wallet instead of your back pocket. Barbers, stylists, and anyone else who works a chair will find their own words in here rather than someone else's. And if you keep a chair of your own, you can flip between the dashboard and your own rewards card without signing out. Sign in with Apple or Google, or with the email you already use. ChairBack takes 0% of what you charge. Card processing is handled by our payment processor, whose own fees apply. Your client list is yours, and you can export it whenever you like. Just looking? There is a demo on both sides, so you can walk through the whole thing first.