# Quarry: SQL & Data Interview — Offline Data Engineer Practice

> Offline Data Engineer Practice (iPhone/iPad app by Mayank Gulaty.)

- Source: https://appshunter.io/ios/app/quarry-sql-and-data-interview/id6785931623 (this page in markdown: same URL + `.md`)
- Developer: [Mayank Gulaty](https://appshunter.io/developer/1850701548)
- Category: Education, Developer Tools
- Price: Free
- Age rating: 4+
- Requires: iOS 18.0 · 128 MB
- Languages: American English
- Released: 2026-07-07
- Data updated: 2026-10-24

## What is Quarry?

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.

## Is Quarry safe?

Not enough ratings yet to assess Quarry.

## Is Quarry legit?

Quarry: SQL & Data Interview has limited verification signals. The AppsHunter Legitimacy Score for Quarry is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 2 releases)

### 1.1 — 2026-10-23

• 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

### 1.0 — 2026-07-07

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-24.*