Quarry: SQL & Data Interview

Offline Data Engineer Practice

Free · Designed for iPad. Not verified for macOS.

Now built for iPhone Duo: the question on one side, your code on the other. 168 SQL, pandas and Python problems, graded on your device, fully offline. Data interview practice that runs entirely on your device. Write real SQL and Python (pandas), get graded instantly, and see exactly why. NEW IN 1.1 • Designed for iPhone Duo: question and editor side by side when open, a focused layout when closed, and it adapts as you fold. • A new native design for iPhone and iPad, in light and dark mode. • 60 new problems: a staff-level data engineering set (gaps and islands, sessionisation, slowly changing dimensions, funnels, retention) and company-style SQL sets. • Clearer results: instant correct / not quite feedback, expected vs. actual tables, and the query plan for your SQL. WHAT'S INSIDE • 168 problems across three tracks: 61 SQL, 22 pandas and 85 Python (algorithms and data structures). • Real execution, real grading. Your output is checked against the expected result, with no self-marking. • Company-style practice. Filter problems written in the style of the company you're interviewing at. • Hints and full solutions when you're stuck. • Difficulty levels from Easy to Hard, grouped by topic. • A free-form Playground for scratch SQL and Python. PRIVATE BY DESIGN No accounts. No analytics. No ads. No tracking. Quarry collects nothing and works fully offline. Built by a working data engineer, for analysts, data engineers, data scientists and software engineers who want a quiet, fast place to actually practice.

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• Designed for iPhone Duo: question and code side by side, adapts as you fold • 60 new problems, including a staff-level data engineering set • New native design with light and dark mode • Clearer results with instant correct or incorrect feedback • See the query plan for your SQL • Bug fixes and performance improvements

Version 1.1

The developer, Mayank Gulaty, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary based, for example, on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Provider
    Mayank Gulaty
    Size
    134.1 MB
    Category
    Education
    Compatibility
    Requires iOS 18.0 or later.
    • iPhone
      Requires iOS 18.0 or later.
    • iPad
      Requires iPadOS 18.0 or later.
    • Mac
      Requires macOS 15.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 2.0 or later.
    Languages
    English
    Age Rating
    4+
    Copyright
    © 2026 Flowbit Studio
  • Privacy Policy

    • More by Mayank Gulaty

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