CodeFlash vs HelloSQL

Code it. Remember it. Flash it! A casual flashcard app for memorizing small bits of code and syntax. It also works as a standard flashcard app, and it now reads your cards aloud — handy for language study too! [ Recommended for ] • Anyone learning programming • People who want to learn common syntax and patterns by heart • Anyone who wants to review on the go or in spare moments • Anyone looking for a personal flashcard app — vocabulary, code, or otherwise [ Features ] ■ Learn by writing code Type code into your cards and run it instantly to check the output. Supports JavaScript, TypeScript, Python, HTML, CSS, SQL, and C++ — learn by doing, not just reading. ■ Read your cards aloud Hear the side you are looking at. Sentences that mix writing systems are read with the right voice for each part, and you can pick the voice and the speed — handy for memorizing vocabulary or reviewing with your ears. ■ Create cards with 3 types of blocks Combine text, code, and image blocks freely. Text blocks support Markdown — headings, lists, bold, tables, and more. ■ Efficient spaced repetition learning The FSRS algorithm adjusts each card's next review to your understanding, for effortless, lasting memorization. ■ Track progress with stats and graphs See your study activity on a contribution graph, plus overall progress, deck mastery, and rating breakdown. ■ Works offline Your learning data is stored on your device (and in your own iCloud when sync is on) and is never sent to external servers. No account registration required. [ Great even on the free plan ] • No limit on the number of decks or cards • No ads • Export / import your data to move it to another device * Existing features will never be moved behind a paywall. [ What you get with Pro ] A one-time purchase. A 7-day free trial is available. • iCloud Sync: sync your data across devices on the same Apple ID. On a new device, just toggle it on to restore everything • HTML / CSS Preview: your code renders as a real page right inside the card. Go full screen to click buttons and type into inputs, or practice DOM manipulation from JavaScript. You can also register shared HTML and images on a deck • SQL / C++ Execution: register deck-wide setup SQL and query the same database from every card • Per-Deck Speech Language: set the reading language for each deck, and a different one for the front and the back • Detailed Statistics: monthly study volume, per-grade rankings (top 10), and per-card performance • Color Themes: 10 presets × light/dark to restyle your cards and the whole app • FSRS Customization: tune review intervals to your own pace — shorter for thorough review, or longer for relaxed learning • Study Timer: a countdown (1–60 min) that runs only while studying. Repeat it for Pomodoro [ Other Features ] • Card search, card duplication, and card transfer between decks • Organize with tags and study across decks • Shuffle cards to study • Set a daily card goal • Archive decks and cards (excluded from study and stats) • JSON export / import (full backup) • TSV export / import (card text and other partial data) • Daily reminder notifications • Dark mode • Bluetooth keyboard shortcuts • Available in English, Japanese, and Spanish • Available on both iPhone and iPad * Running HTML, CSS, SQL, and C++, and previewing JavaScript, are Pro features. Reading cards aloud is free. * Internet is required only for iCloud sync and running Python / C++ (Python loads its execution environment; C++ is sent to Wandbox, an external service — no account or personal info is included). Try the free version first!

SQL tends to make sense while you're reading about it, then fall apart the moment you try to write it yourself. HelloSQL is for the writing part. You read a problem, write a query, and run it. The results show up as a table, and if they're right, it's marked correct right away. Grading looks at what your query returns, not how it's written, so your query doesn't have to match ours. There are 120 exercises, and most of them look like everyday reporting tasks. For example: "List payments from largest to smallest. If two amounts are the same, put the older one first." The practice data is built around an online store's orders, employee attendance, and billing for a subscription service. What's free and what isn't The first 30 exercises are free, and you don't need an account. They cover SELECT, WHERE, ORDER BY, and LIMIT. The other 90 move on to aggregate functions, GROUP BY, HAVING, INNER JOIN, LEFT JOIN, CASE, subqueries, CTEs, and window functions. You unlock all of them with one in-app purchase. There's no subscription and nothing recurring. When you're stuck Each exercise has three hints, and you open them one at a time. The first gives you only the idea. If that's not enough, the second shows the shape of the query, and the third tells you which tables and columns to use. We set it up this way so you don't have to jump straight to the answer. There's also a sample solution with an explanation, and you can tap any underlined term in a problem to see what it means. Coming back to it Your drafts save automatically, so you can close the app halfway through a query and finish it later. Missed exercises and bookmarks are kept together so you can try them again. Anything you get wrong comes back the next day. Exercises you get right come back too, after 3 days, then a week, then 3 weeks. The editor suggests SQL keywords and column names as you type, and you can look at the tables and their data at any point. It works on iPhone and iPad, in light or dark mode. If you've gone through a course or a book and want to actually use what you learned, this is a good next step. It also works as a warm-up before a SQL test or a technical interview. Before you download • The practice data is set in Japan, so some names, places, and text values are in Japanese. A few exercises ask you to type Japanese text into your query, such as WHERE city = '東京'. The exercise shows you the exact text to use. • You can practice and check answers offline. You only need a connection to buy or restore the unlock. • There are no ads. Exercise 1 is a single line that pulls every customer's name. It's a good place to start.