Comparison

SQL Practice vs Scan21

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

SQL Practice

Master SQL with short, daily interactive sessions. Practice real-world queries and datasets on your phone to build confidence for career changes, professional development, or technical interviews. Learn database concepts and advanced techniques at your own pace.

Highlights
  • 15-minute daily learning sessions
  • Interactive exercises with real-world datasets
  • Progressive curriculum from beginner to advanced
  • Instant feedback and mistake analysis
  • Gamified progress tracking (streaks, XP, achievements)
  • Master SELECT, JOINs, aggregations, and subqueries
Read full description

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

About

Scan21

Quickly verify if individuals meet the 21+ age requirement by scanning the barcode on their ID. Get instant visual and audio feedback for eligibility. Works offline and tracks scan history.

Highlights
  • Scan ID barcodes with device camera
  • Automatic age calculation for 21+
  • Clear visual (green/red screen) feedback
  • Optional audio alerts
  • Scan history and statistics
  • Offline functionality
Features
Read full description

Scan21 – Age ID Check helps you quickly verify if someone meets the 21+ legal age requirement by scanning the barcode on their ID. Perfect for bars, clubs, liquor stores, dispensaries, or any venue requiring instant age checks. Simply scan, and the app will automatically calculate the age, alerting you with clear visual and audio feedback. Features: Fast & Accurate Scanning – Uses your device camera to read ID barcodes. Automatic Age Calculation – Instantly determines if the person is 21+. Clear Visual Feedback – Green screen for eligible, red screen for ineligible. Audio Alerts – Optional success/failure tones for quick recognition. Scan History & Stats – Tracks the total number of successful and failed scans. Simple & Reliable – No internet required, works offline. This tool is designed to make age verification quick, professional, and hassle-free. Disclaimer: This app is for age screening assistance only and should not replace manual ID verification. Always follow your local laws and regulations.

Screenshots

SQL Practice4 screens
Scan214 screens

Verdict

The call

The clearest difference is review sentiment: SQL Practice at 85% against Scan21's 0%. SQL Practice also leads on price (Free vs $1.99) and rating (4.7 vs 2.3). Scan21's advantage is in-app purchases (none vs 2) and chart position (#25 vs #91). On ads, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

SQL Practice is free to download; Scan21 costs $1.99 up front. SQL Practice sells 2 in-app purchases, starting at $3.99 per 7 days. Scan21 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

SQL Practice holds the better App Store score, 4.7 against 2.3. That said, the two scores are not equally well evidenced: SQL Practice has 137 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 85% of SQL Practice's written reviews are positive against 0% of Scan21's.

Scorecard7 real differences · 4 level
SQL Practice versus Scan21: the parameters behind the verdict, then further details
ParameterSQL PracticeScan21
PriceFree — better$1.99
Rating4.7 (137 ratings) — better2.3 (3 ratings)
Positive reviews85.3% of reviews — better0.0% of reviews
Number of ratings137 — better3
Update frequencyEvery 6 months—
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree — betterPaid
Best chart rank#91#25 — better
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS13.013.0
Further details — not scored
Size48 MB22 MB
Age rating4+4+
DeveloperMarton GreberTelliSIM - Travel eSIM solutions

Customer experience

SQL Practice

All ratings137 ratings
Positive92.7%
Neutral3.6%
Negative3.6%
Written reviews34 reviews
Positive85.3%
Neutral8.8%
Negative5.9%

Scan21

All ratings3 ratings
Positive33.3%
Neutral0.0%
Negative66.7%
Written reviews2 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

2 purchases

SQL Practice

Subscriptions2
  • Pro Access3 Days trial$3.997 Days
  • Pro Access$19.991 Year
None

Scan21

No in-app purchases

Questions

Is SQL Practice free?
SQL Practice is free to download, with in-app purchases available.
Is Scan21 free?
Scan21 costs $1.99, with no in-app purchases.
Which has better reviews, SQL Practice or Scan21?
SQL Practice is rated higher. SQL Practice averages 4.7 out of 5 from 137 ratings, while Scan21 averages 2.3 from 3 ratings.
Do SQL Practice or Scan21 have ads?
Neither SQL Practice nor Scan21 shows ads.
Which is more popular, SQL Practice or Scan21?
SQL Practice currently peaks at #91 in the App Store charts, and Scan21 at #25. Chart position reflects recent download velocity rather than total install base.

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