Chief Fox at his desk, reading a case file by the light of an orange lamp, with a night skyline through the arched window behind him

Learn SQL & Excel.
One mystery at a time.

Build real data skills through detective cases. Write queries, uncover clues, and solve the mystery.

Beginner-friendlyRuns in your browser
2,400+learners
116countries
17,300+cases solved

COURSES

Learn SQL and Excel by solving cases

A full curriculum played as detective cases, in the browser, with nothing to install. Free to start.

SELECT name, alibi
FROM suspects
WHERE alibi IS NULL
namealibi
MarloweNULL
SQLBeginner to advanced

From your first SELECT through joins and grouping to window functions, queried against a real database.

SELECT & WHEREGROUP BYJOINsWindow functions
View course
C2fx=XLOOKUP(A2,badge,shift)
BadgeNameShift
4417Marlowe
2290DiazDays
ExcelBeginner to advanced

Lookups, text clean-up, conditional formatting and pivot tables, worked on a real spreadsheet engine.

XLOOKUPSUMIFSPivot tablesConditional formatting
View course
Coming soon
>>> cases.groupby("case").size()
Donut 3
Corridor 5
PythonIn the works

Lists, loops and functions, through to reading files and analysing real data with pandas.

Lists & loopsFunctionspandas
In development

YOUR PROGRESS, CASE BY CASE

Make “one more case” a habit

It works like a game because it is one. A clear next step, progress you can see, and a new rank to work towards.

YOUR DESKExample progressSQL
Up next
Parking Lot IncidentCase 002Rookie Detective+75 XP

Your case board

1 rank · It ends with an exam.

Case 001The Missing DonutSolved+50 XP
Case 002Parking Lot Incident+75 XP
Case 003The Vanishing Witness+100 XP
Drill 001First Filters+50 XP
Case 004The Chop Shop+100 XP
Case 005The Witching Hour+100 XP
Case 006The Fake Badge+75 XP
Drill 002Operator Roundup+50 XP
Case 007Top of the List+75 XP
Case 008The Pattern+75 XP
Rank examRookie Graduation+250 XP
See your progressEvery solved case moves you along your learning path.
Build your routineKeep your day streak going, one case at a time.
Earn your rankPass rank exams from Recruit to Chief Detective, collect titles and share certificates.
See where you standA global Leaderboard, and a profile worth sending to someone.

BEYOND THE LEARNING PATH

Ready to go further?

Explore freely in the Sandbox, or put what the cases taught you to the test in an Investigation.

Explore at your own pace

Sandbox

Pick a dataset you already know, ask it whatever you want, and read the rows that come back. Bring your own CSV if you would rather.

Real datasetsYour own CSVsCharts

Take on a challenge

Investigations

A full mystery across several tables and three acts, with a clock running and no walkthrough to follow. When you think you have it, you get one accusation.

TimedNo hints

THE PEOPLE BEHIND THE PROGRESS

Learning that clicks.

From a first SQL query to the final case.

I know basic SQL and honestly I did not understand window functions and some advanced concepts until I started querying in QueryCase. You have put all the concepts up in a structured manner.
Data engineerFinished all 54 cases
This is my first approach to SQL in my life, and it is very intuitive. I finished the free cases already, and I was surprised when I looked at the price and saw it was one payment.
New to SQLvia Reddit
I am a second year data science student and it would have been great to have this in my relational database management systems unit. This website makes it feel easy, and most importantly, engaging.
Data science studentvia Reddit
Used in a US college labWeekend lab · 4 hours of practice

“Students strengthened their SQL skills through interactive challenges on QueryCase.”

Course instructor · CompTIA Data+ cohort, 2026

FOR EDUCATORS

Your classroom.
Your precinct.

Give students a case to crack. Keep their progress in view.

  • A fun way to practiseGuided cases turn learning into a problem to solve.
  • See how your class is doingTrack completed cases, XP and recent activity.
  • Follow individual progressOpen a student's record to explore their learning path.

Tell us about your group and what you teach.

Case-based learning for students. A clear view of progress for you.

YOUR FIRST CASE IS WAITING

Your first case.
Your next skill.

Learn SQL and Excel by solving mysteries. Start with a free case. Build skills that stick.

No experience neededNo credit card required