# QueryCase

> QueryCase is a SQL detective game with a real course behind it. You write real SQL against an in-browser database to crack mystery cases, with no install and no signup needed to start. Unlike one-off SQL games (SQL Murder Mystery, SQL Island), which end after a single puzzle at SELECT/WHERE/JOIN, QueryCase is a full curriculum that continues through GROUP BY, HAVING, subqueries, CTEs and window functions.

## What it is

QueryCase teaches SQL through narrative "case files" instead of dry exercises. Each case is a mystery you solve by writing queries, so every query you run is answering a question that matters to the story. It runs entirely in the browser (DuckDB compiled to WebAssembly), so there is nothing to install and no database to configure. It suits complete beginners through to people brushing up for data-analyst and data-engineering interviews.

## What makes it different

- Learn by doing, not watching: you write and run real SQL from the first minute.
- Purpose over abstraction: queries answer story questions, which is why the concepts stick.
- A progressive curriculum of 54 guided cases across five detective ranks (Recruit, Rookie Detective, Detective, Senior Detective, Chief Detective), from SELECT to window functions, with 12 drills and 4 rank exams.
- Hints when you are stuck, drills between topics, timed challenges (Investigations), and a Sandbox of real datasets: IMDb Ratings, Metro Crime, TechCart, Pokemon, Spotify Wrapped, NBA 2024-25 and Steam Games, 44 tables between them, with cross-dataset JOINs. IMDb Ratings and Metro Crime are free. Anyone with an account can load one of their own CSV files into the Sandbox and query it with SQL; Full Access raises that to five files at once so they can be joined together. Those files are parsed by DuckDB inside the browser and are never uploaded to QueryCase or stored on any server.
- A Career Hub for job seekers: company-style SQL interview questions, a rapid multiple-choice SQL quiz (Quickfire), and a guide to data-career roles.

## What you learn

SELECT and WHERE, filtering and operators, ORDER BY and LIMIT, aggregates and GROUP BY, HAVING, JOINs (INNER, LEFT, RIGHT, FULL), subqueries and CTEs, CASE expressions, date handling, and window functions (ROW_NUMBER, RANK, LAG and LEAD).

## Career Hub (SQL interview practice)

Beyond the core curriculum, QueryCase has a Career Hub aimed at landing a data job:

- [Interview Prep](https://querycase.com/career-hub/interview-prep): real, company-style SQL interview questions modelled on the loops at Meta, Amazon, Netflix, Google, Airbnb, Spotify, Snapchat, Robinhood, Lyft, Coinbase and Twitter. Each question page is public: anyone can read the prompt, the schema and the target output, and each opens in a SQL editor that checks your answer and reveals a worked solution plus the insight most candidates miss. Running queries takes a free account. Several questions are free; the rest unlock with Full Access.
- MCQ Quickfire (a rapid SQL quiz): hundreds of multiple-choice quiz questions spanning SQL behaviour, query performance, statistics, A/B testing, Python and pandas, data modelling, business metrics, data quality and the modern data stack, each with an instant explanation.
- [Data Roles](https://querycase.com/career-hub/roles): a public guide to the six core data roles (Data Analyst, BI Analyst, Analytics Engineer, Data Scientist, Data Engineer, ML Engineer), where each sits on the analyze-to-build spectrum, and the SQL each one actually writes. Printable as a PDF.

## Pricing

Free tier: the Rookie Detective arc (10 cases plus the Rookie exam plus cheat sheet access). Full Access: a one-time payment of £14.99 (localised: $17.99 USD, €16.99 EUR), with no subscription and no recurring charges. Regional pricing is available in many countries, set for local purchasing power rather than converted from GBP (for example ₹999 in India). It unlocks every case, all drills and rank exams, all Investigations, and the full Sandbox with cross-dataset JOINs, plus five of your own CSV files at once instead of one. All future content is included.

## Site

- [Homepage](https://querycase.com): What QueryCase is, who it's for, free signup
- [Pricing](https://querycase.com/pricing): Plan comparison and FAQ
- [About](https://querycase.com/about): The full SQL curriculum: every rank, what each one teaches, the drills, exams, Investigations, Sandbox datasets and the complete list of SQL covered, plus why QueryCase exists
- [Contact](https://querycase.com/contact): hello@querycase.com

## Learning resources

- [SQL Cheat Sheet](https://querycase.com/cheat-sheet): Free reference of SQL syntax, SELECT, WHERE, JOIN, GROUP BY, window functions, CTEs
- [Career Hub](https://querycase.com/career-hub): SQL interview prep, the Quickfire quiz and the data-roles guide in one place
- [SQL Interview Questions](https://querycase.com/career-hub/interview-prep): Company-style SQL interview questions, each solvable in the browser
- [Data Roles Explained](https://querycase.com/career-hub/roles): The six core data roles, the analyze-to-build spectrum, and the SQL each writes
- [Blog](https://querycase.com/blog): Tutorials and SQL learning guides

### Articles

Each article is also available as clean markdown by appending .md to its URL.

- [SQL Murder Mystery: A Walkthrough That Doesn't Spoil It](https://querycase.com/blog/sql-murder-mystery-walkthrough): Stuck on the SQL Murder Mystery? A hint-by-hint walkthrough that teaches you how to attack an unfamiliar database, with the queries explained and the answer left to you. (markdown: https://querycase.com/blog/sql-murder-mystery-walkthrough.md)
- [Build an IMDb Movie Dashboard with SQL and Tableau (Free Beginner Project)](https://querycase.com/blog/build-an-imdb-dashboard-with-sql-and-tableau): A free beginner data project: write three SQL queries on real IMDb data, then build an interactive Tableau dashboard for your portfolio. No installs. (markdown: https://querycase.com/blog/build-an-imdb-dashboard-with-sql-and-tableau.md)
- [SQL Practice Questions (With Answers, Easy to Hard)](https://querycase.com/blog/sql-practice-questions): Ten SQL practice questions with worked answers, easy to hard: filtering, GROUP BY, joins, HAVING and window functions, the patterns interviews test. (markdown: https://querycase.com/blog/sql-practice-questions.md)
- [The Best SQL Games and Learning Resources (2026)](https://querycase.com/blog/best-sql-games-and-learning-resources): The complete guide to SQL games and learning resources in 2026. Which teach a full curriculum, which are one-off puzzles, and which stop at JOIN. (markdown: https://querycase.com/blog/best-sql-games-and-learning-resources.md)
- [WHERE vs HAVING in SQL: The Difference, Explained](https://querycase.com/blog/where-vs-having): WHERE filters rows before grouping; HAVING filters groups after. See the difference run live, plus the aggregate rule that trips everyone up. (markdown: https://querycase.com/blog/where-vs-having.md)
- [SQL Order of Execution: How Queries Actually Run](https://querycase.com/blog/sql-order-of-execution): The SQL order of execution: FROM runs first, SELECT almost last. It explains alias errors, HAVING vs WHERE, and why you cannot filter a window function. (markdown: https://querycase.com/blog/sql-order-of-execution.md)
- [SQL CASE WHEN Explained (Simple vs Searched, ELSE & Pivots)](https://querycase.com/blog/sql-case-when-explained): SQL CASE WHEN is if/else for your queries: check conditions in order, return the first match. See CASE, ELSE and pivots run live in an interactive demo. (markdown: https://querycase.com/blog/sql-case-when-explained.md)
- [Introducing the Career Hub: Practice SQL Interviews for Real](https://querycase.com/blog/introducing-the-career-hub): Meet the QueryCase Career Hub: company-style SQL interview questions in a live editor, a rapid Quickfire quiz, and a map of data roles. Free to start. (markdown: https://querycase.com/blog/introducing-the-career-hub.md)
- [SQL OVER Clause & Window Functions Explained (ROW_NUMBER, RANK)](https://querycase.com/blog/sql-window-functions-explained): The SQL OVER clause turns SUM, ROW_NUMBER and RANK into window functions that keep every row. See OVER, PARTITION BY and ORDER BY work live in an interactive demo. (markdown: https://querycase.com/blog/sql-window-functions-explained.md)
- [SQL JOINs Explained: A Visual, Interactive Guide](https://querycase.com/blog/sql-joins-explained): Finally understand SQL JOINs. Pick INNER, LEFT, RIGHT or FULL and watch exactly which rows match, drop, and combine in a live interactive diagram. (markdown: https://querycase.com/blog/sql-joins-explained.md)
- [How to Learn SQL Fast (Without Boring Yourself to Death)](https://querycase.com/blog/how-to-learn-sql-fast): Most people quit SQL because the data they practise on is boring. Learn SQL fast by querying data you actually care about, in the right order to make it stick. (markdown: https://querycase.com/blog/how-to-learn-sql-fast.md)
- [How to Prepare for a SQL Interview: What Actually Comes Up](https://querycase.com/blog/sql-interview-questions): How to prepare for a SQL interview: what hiring managers actually test, the query patterns that come up everywhere, and the company-specific layer most candidates skip. (markdown: https://querycase.com/blog/sql-interview-questions.md)