Now we have lots of challenges, to make the site a little easier to navigate here is a link to all of the individual challenges and their solution posts.
Don't forget to fill out the Participation Tracker. You can check which challenges you have completed here.

2024

Introductory Month
Week 1: Challenge  Solution  Video  Prep Air's Flow Card
Week 2: Challenge  Solution  Video  Average Price Analysis

Week 3: Challenge  Solution  Video  Performance Against Targets

Week 4: Challenge  Solution  Video  Unpopular Seats

Week 5: Challenge  Solution  Video  Getting The Right Data

Intermediate Month

Week 6: Challenge  Solution  Video  Staff Income Tax

Week 7: Challenge  Solution  Video  Valentine's Day

Week 8: Challenge  Solution  Video  Prep Air Loyalty

Week 9: Challenge  Solution  Video  Prep Air Capacity

Week 10: Challenge  Solution  Video  Preppin' for Pulse

Week 11: Challenge  Solution  Video  13 Months in a Year

Week 12: Challenge  Solution  Video  Graduate Student Loan Repayments

Week 13: Challenge  Solution  Video  Easter Sales

Week 14: Challenge  Solution  Video  Store Data

Week 15: Challenge  Solution  Video  Store Data Part 2

Week 16: Challenge  Solution  Video  Budget vs Actuals

Week 17: Challenge  Solution  Video  Budget vs Actuals Part 2

Week 18: Challenge  Solution  Video  San Diego Zoo TC24 Special

Week 19: Challenge  Solution  Video  SuperBytes Sales and Profits

Week 20: Challenge  Solution  Video  SuperBytes Customer Data

Week 21: Challenge  Solution  Video  Loyalty Points Percentages

Week 22: Challenge  Solution  Video  Top 5 Loyal Customers

Week 23: Challenge  Solution  Video  SuperBytes Salaries

Week 24: Challenge  Solution  Video  SuperBytes Salaries Part 2

Week 25: Challenge  Solution  Video  SuperBytes Customer Complaints

Week 26: Challenge  Solution  Video  SuperBytes Customer Complaints Part 2

Week 27: Challenge  Solution  Video  Tour de France Special

Week 28: Challenge  Solution  Video  Wimbledon Special

Week 29: Challenge  Solution  Video  Formula 1 Qualifying Special

Week 30: Challenge  Solution  Video  International Football Special

Week 31: Challenge  Solution  Video  Olympics Special

Week 32: Challenge  Solution  Video  Pokémon Card Organising

Week 33: Challenge  Solution  Video  The Prep School Birthday Cakes Part 2

Week 34: Challenge  Solution  Video  The Prep School Birthday Cakes Part 3

Week 35: Challenge  Solution  Video  Premier League Results

Week 36: Challenge  Solution  Video  Premier League Standings

Week 37: Challenge  Solution  Video  Premier League Recent Form

Week 38: Challenge  Solution  Video  Preppin' Consultancy Days

Week 39: Challenge  Solution  Video  Preppin' Consultancy Ranks

Week 40: Challenge  Solution  Video  Vrroom

Week 41: Challenge  Solution  Video  Forbes Highest Paid Athletes

Week 42: Challenge  Solution  Video  Strictly Come Dancing

Week 43: Challenge  Solution  Video  MiniBytes Worst Selling Products

Week 44: Challenge  Solution  Video  MiniBytes Returns Analysis

Week 45: Challenge  Solution  Video  SuperBytes Stock

Week 46: Challenge  Solution  Video  DataFam Europe Special

2023

Introductory Month
Week 1: Challenge  Solution  Video  The Data Source Bank

Week 2: Challenge  Solution  Video  International Bank Account Numbers

Week 3: Challenge  Solution  Video  Targets for DSB

Week 4: Challenge  Solution  Video  New Customers


Intermediate Month

Week 5: Challenge  Solution  Video  DSB Ranking

Week 6: Challenge  Solution  Video  DSB Customer Ratings
Week 7: Challenge  Solution  Video  Flagging Fraudulent Suspicions 

Week 8: Challenge  Solution  Video  Taking Stock

Advanced Month

Week 9: Challenge  Solution  Video  Customer Bank Statements

Week 10: Challenge  Solution  Video  What's my Balance on this Day?

Week 11: Challenge  Solution  Video  Which Customers are Closest?

Week 12: Challenge  Solution  Video  Regulatory Reporting Alignment

Week 13: Challenge  Solution  Video  Rolling Stock Price Trends

Week 14: Challenge  Solution  Video  World Trade Data

Week 15: Challenge  Solution  Video  Easter Date

Week 16: Challenge  Solution  Video  Easter and Full Moons

Week 17: Challenge  Solution  Video  Population Growth vs Country Size

Week 18: Challenge  Solution  Video  The Nut House Revenue Analysis

Week 19: Challenge  Solution  Video  Tableau Conference Special

Week 20: Challenge  Solution  Video  Dining Hall Debacle

Week 21: Challenge  Solution  Video  Prep School Grades

Week 22: Challenge  Solution  Video  Student Attendance vs Test Scores

Week 23: Challenge  Solution  Video  Is it the teacher or the student? Part 1

Week 24: Challenge  Solution  Video  Is it the teacher or the student? Part 2

Week 25: Challenge  Solution  Video  Prep School 2023 Admissions - Part 1

Week 26: Challenge  Solution  Video  Prep School 2023 Admissions - Part 2

Week 27: Challenge  Solution  Video  The Cost of Running the Prep School

Week 28: Challenge  Solution  Video  Prep School Track Team
Week 29: Challenge  Solution  Video  Moving Averages

Week 30: Challenge  Solution  Video  % Difference From

HR Month

Week 31: Challenge  Solution  Video  Filling in Missing IDs

Week 32: Challenge  Solution  Video  Reshaping Generations

Week 33: Challenge  Solution  Video  Combinations

Week 34: Challenge  Solution  Video  Turnover Rate

Week 35: Challenge  Solution  Video  Transfers

Week 36: Challenge  Solution  Video  C&BSCo 5-a-side

Week 37: Challenge  Solution  Video  Order Sequence Analysis

Week 38: Challenge  Solution  Video  Sustainable Development Goals

Week 39: Challenge  Solution  Video  Tennis 200 Club

Week 40: Challenge  Solution  Video  Prep School Subject Dropouts

Week 41: Challenge  Solution  Video  An International School 

Week 42: Challenge  Solution  Video  Prep School "Disco Fever"

Week 43: Challenge  Solution  Video  Best Attendance Awards

Week 44: Challenge  Solution  Video  Prep School Spring Calendar

Week 45: Challenge  Solution  Video  Fill Down

Week 46: Challenge  Solution  Video  Late for School

Week 47: Challenge  Solution  Video  Student GPA

Week 48: Challenge  Solution  Video  Reporting Week Calendars

Week 49: Challenge  Solution  Video  Regular Savings Accounts

Week 50: Challenge  Solution  Video  Regular Savings Accounts - Part 2

Week 51: Challenge  Solution  Video  Elf Toy Production

Week 52: Challenge  Solution  Video  Preppin' Classification

2022

Week 1: Challenge Solution Video The Prep School - Parental Contact Details

Week 2: Challenge Solution Video The Prep School - Birthday Cakes

Week 3: Challenge Solution Video The Prep School - Passing Grades

Week 4: Challenge Solution Video The Prep School - Travel Plans

Week 5: Challenge Solution Video The Prep School - Setting Grades

Week 6: Challenge Solution Video 7 Letter Scrabble Words

Week 7: Challenge Solution Video Call Centre Agent Metrics

Week 8: Challenge Solution Video Pokemon Evolution Stats

Week 9: Challenge Solution Video Customer Classifications

Week 10: Challenge Solution Video The Bechdel test

Week 11: Challenge Solution Video The Prep School - Filling the Blanks

Week 12: Challenge Solution Video Gender Pay Gap

Week 13: Challenge Solution Video Pareto Parameters

Week 14: Challenge Solution Video House of Games Winners

Week 15: Challenge Solution Video Property Management

Week 16: Challenge Solution Video Restaurant Orders

Week 17: Challenge Solution Video The Price of Streaming

Week 18: Challenge Solution Video Un-Pivoting

Week 19: Challenge Solution Video Good Sales, Wrong Sizes

Week 20: Challenge Solution Video TC22 Session Attendance

Week 21: Challenge Solution Video Multi-Sheets of Madness

Week 22: Challenge Solution Video Dungeons & Dragons: Critical Role

Week 23: Challenge Solution Video PD x WOW Salesforce Opportunities

Week 24: Challenge Solution Video Longest Flights

Week 25: Challenge Solution Video Housing Happy Hotel Guests

Week 26: Challenge Solution Video Making Spotify Data Spotless

Week 27: Challenge Solution Video C&BSCo Clean and Aggregate

Week 28: Challenge Solution Video C&BSCo No Sales Today

Week 29: Challenge Solution Video C&BSCo Meeting Targets?

Week 30: Challenge Solution Video C&BSCo Actual Sales Values

Week 31: Challenge Solution Video C&BSCo Preppin' Parameters

Week 32: Challenge Solution Video C&BSCo Mortgage Repayments

Week 33: Challenge Solution Video C&BSCo Next Sale

Week 34: Challenge Solution Video C&BSCo Parameters, Parameters, Parameters

Week 35: Challenge Solution Video C&BSCo Summary Stats

Week 36: Challenge Solution Video Calendar Conundrum

Week 37: Challenge Solution Video Elden Ring Adventure

Week 38: Challenge Solution Video Salesforce Standard Connections for Dreamforce 22

Week 39: Challenge Solution Video Filling in for HR

Week 40: Challenge Solution Video Times Tables

Week 41: Challenge Solution Video Dynamic Times Tables

Week 42: Challenge Solution Video Missing Training Data

Week 43: Challenge Solution Video Missing Training Data 2.0

Week 44: Challenge Solution Video Creating Order IDs

Week 45: Challenge Solution Video Strange Table Structure

Week 46: Challenge  Solution  Video  Dynamically Fixing Table Structures

Week 47: Challenge  Solution  Video  Chelsea Managers per Prime Minister

Week 48: Challenge  Solution  Video  Tiddlywinks Tidy

Week 49: Challenge  Solution  Video  Cleaning Status History (HR month)

2021

Week 1: Challenge Solution Video New Year, New Challenge

Week 2: Challenge Solution Video Bike Store Sales

Week 3: Challenge Solution Video Bike Accessory Sales

Week 4: Challenge Solution Video Bike Sales Targets

Week 5: Challenge Solution Video Dealing With Duplication

Week 6: Challenge Solution Video Comparing Prize Money for Professional Golfers

Week 7: Challenge Solution Video Vegan Shopping List

Week 8: Challenge Solution Video Karaoke Data

Week 9: Challenge Solution Video Working with Strings

Week 10: Challenge Solution Video Pokemon Hierarchies

Week 11: Challenge Solution Video Cocktail Profit Margins

Week 12: Challenge Solution Video Maldives Tourism

Week 13: Challenge Solution Video Premier League Statistics

Week 14: Challenge Solution Video Prep Air In-Flight Purchases

Week 15: Challenge Solution Video Restaurant Menu & Orders

Week 16: Challenge Solution Video The Super League

Week 17: Challenge Solution Video Timesheet Checks

Week 18: Challenge Solution Video Prep Air Project Overruns

Week 19: Challenge Solution Video Prep Air Project Details

Week 20: Challenge Solution Video Controlling Complaints

Week 21: Challenge Solution Video Getting Trolleyed

Week 22: Challenge Solution Video Answer Smash

Week 23: Challenge Solution Video NPS for Airlines

Week 24: Challenge Solution Video C&BS Co: Absence Monitoring

Week 25: Challenge Solution Video The Worst Pokemon

Week 26: Challenge Solution Video Rolling Weekly Revenue

Week 27: Challenge Solution Video NBA Draft Lottery calculator

Week 28: Challenge Solution Video It's Coming Rome

Week 29: Challenge Solution Video PD x WOW - Tokyo 2020 Calendar

Week 30: Challenge Solution Video Lift Your Spirits

Week 31: Challenge Solution Video Excelling in Prep

Week 32: Challenge Solution Video Excelling through aggregation

Week 33: Challenge Solution Video Excelling at adding one more row

Week 34: Challenge Solution Video Excelling with lookups

Week 35: Challenge Solution Video Picture perfect

Week 36: Challenge Solution Video What's trendy?

Week 37: Challenge Solution Video Re-looking at phone contract revenue

Week 38: Challenge Solution Video Trilogy

Week 39: Challenge Solution Video Painting bikes

Week 40: Challenge Solution Video Animal adoptions

Week 41: Challenge Solution Video Southend Stats

Week 42: Challenge Solution Video Charity Fundraising

Week 43: Challenge Solution Video Is that the case?

Week 44: Challenge Solution Video On yer bike!

Week 45: Challenge Solution Video Spread the Knowledge for TC!

Week 46: Challenge Solution Video Bookshop Data Modelling

Week 47: Challenge Solution Video Games Night Viz Collab

Week 48: Challenge Solution Video Departmental December - Finance

Week 49: Challenge Solution Video Departmental December - Human Resources

Week 50: Challenge Solution Video Departmental December - Sales

Week 51: Challenge Solution Video Departmental December - IT

Week 52: Challenge Solution Video Departmental December - Operations

2020
Week 1: Challenge   Solution   Video   Accounting Formatting
Week 2: Challenge   Solution   Video  Cleaning Time
Week 3: Challenge   Solution   Video  NBA Standings
Week 4: Challenge   Solution   Video  C&BS Co: Store Survey deduplication
Week 5: Challenge   Solution   Video  Technique: Standard Competition Rank
Week 6: Challenge   Solution   Video  C&BS Co: Currency Conversion
Week 7: Challenge   Solution   Video  Counting People Past & Present
Week 8: Challenge   Solution   Video  Comparing Actuals vs Budget / Profitable levels
Week 9: Challenge   Solution   Video  C&BS Co: Political Monitoring
Week 10: Challenge   Solution   Video  C&BS Co: A Logic Grid Puzzle
Week 11: Challenge   Solution   Video  C&BS Co: Knapsack Problem
Week 12: Challenge   Solution   Video  C&BS Co: Messy Data Clean Up
Week 13: Challenge   Solution   Video  C&BS Co IT:  Analysing Support Desk SLA Compliance
Week 14: Challenge   Solution   Video  Preppin' Data to Build a Spider Chart
Week 15: Challenge   Solution   Video  Market Basket Analysis
Week 16: Challenge   Solution   Video  Preppin' the un-Visualisable
Week 17: Challenge   Solution   Video  Netflix Usage
Week 18: Challenge   Solution   Video  Liverpool Line-ups
Week 19: Challenge   Solution   Video  Liverpool Line-ups (Part 2)
Week 20: Challenge   Solution   Video  Cipher Solving

Week 21: Challenge   Solution   Video  Competitor Analysis
Week 22: Challenge   Solution   Video  Creating Data

Week 23: Challenge   Solution   Video  Let's Get Quizzical

Week 24: Challenge   Solution   Video  Historical Battles

Week 25: Challenge   Solution   Video  Roman Numerals

Week 26: Challenge   Solution   Video  Matching IDs

Week 27: Challenge   Solution   Video  Surf's Up!

Week 28: Challenge   Solution   Video  Olympic Dates

Week 29: Challenge   Solution   Video  Event Refunds

Week 30: Challenge   Solution   Video  What's the Weather?

Week 31: Challenge   Solution   Video  When PD met Workout Wednesday Again!

Week 32: Challenge   Solution   Video  Fill Down Challenge

Week 33: Challenge Solution Video Fill Down Challenge 2

Week 34: Challenge Solution Video C&BS Co: Profitability Analysis

Week 35: Challenge Solution Video C&BS Co: Restructuring Excel data

Week 36: Challenge Solution Video Back to School: Teacher allocations

Week 37: Challenge Solution Video Working Days

Week 38: Challenge   Solution   Video  Anagrams or Snag a Ram?

Week 39: Challenge Solution Video Prep a Manger

Week 40: Challenge Solution Video What Were William's Words Worth?

Week 41: Challenge Solution Video Tableau Conference-ish!

Week 42: Challenge Solution Video Progress to Date tracking

Week 43: Challenge Solution Video Baby Names

Week 44: Challenge Solution Video Spooky Sales

Week 45: Challenge Launching Prep Air

Week 46: Challenge Solution Video Aviation Incidents

Week 47: Challenge Solution Video Prep Air Delays

Week 48: Challenge Solution Video Gate Allocation Problem

Week 49: Challenge Solution Video NBA Rankings

Week 50: Challenge Solution Video Secret Santa

Week 51: Challenge Solution Video NBA Travel Times

Week 52: Challenge Solution Video US Women's Championship Golf

Week 53: Challenge Solution Video Changing Star Signs


2019

Week 1: Challenge   Solution   What colour cars are selling?

Week 2: Challenge   Solution   Windy, wet or both?

Week 3: Challenge   Solution   Mobile phone contract revenue

Week 4: Challenge   Solution   NBA player profile (pane) analysis

Week 5: Challenge   Solution   Balances, statements, and complaints

Week 6: Challenge   Solution   C&BS Co: purveyors of soap

Week 7: Challenge   Solution   C&BS Co: bubbling distribution problems

Week 8: Challenge   Solution   C&BS Co: accounting for slippery thieves

Week 9: Challenge   Solution   C&BS Co: scouring Twitter feedback

Week 10: Challenge   Solution   C&BS Co: freshening up a mailing list

Week 11: Challenge   Solution   Parsing JSON data

Week 12: Challenge   Solution   C&BS Co: sanitizing system downtime

Week 13: Challenge   Solution   C&BS Co: sniffing out balance issues

Week 14: Challenge   Solution   Meal deals at Whyte's Cafe

Week 15: Challenge   Solution   Finding weird client behaviour

Week 16: Challenge   Solution   C&BS Co: a 15 perScent discount!

Week 17: Challenge   Solution   Arrow's Impossibility Theorem

Week 18: Challenge   Solution   C&BS Co: Endless Legend of the Soap Heroes

Week 19: Challenge   Solution   C&BS Co: mud, sweat, & bicycle gears

Week 20: Challenge   Solution   C&BS Co: paying for hospital scrubs - Part 1
Week 21: Challenge   Solution   C&BS Co: paying for hospital scrubs - Part 2
Week 22: Challenge   Solution   Calculating a moving average
Week 23: Challenge   Solution   Creating TitleCase Text
Week 24: Challenge   Solution   What's up with WhatsApp?
Week 25: Challenge   Solution   When PD met Workout Wednesday
Week 26: Challenge   Solution   No typed calculations allowed!
Week 27: Challenge   Solution   C&BS Co: Valentine's analysis
Week 28: Challenge   Solution   C&BS Co: People time recording
Week 29: Challenge   Solution   C&BS Co: Subscription package financial model
Week 30: Challenge   Solution   Serpentine Swimming Club
Week 31: Challenge   Solution   C&BS Co: Orders and Operational Stats
Week 32: Challenge   Solution   C&BS Co: Multiple products, multiple columns
Week 33: Challenge   Solution   C&BS Co: HR data from multiple sources
Week 34: Challenge   Solution   C&BS Co: Supplier Timings part I
Week 35: Challenge   Solution   C&BS Co: Supplier Timings part II
Week 36: Challenge   Solution   Reusable Steps - Metric Conversion
Week 37: Challenge   Solution   Aggregations, aggregations and more aggregations
Week 38: Challenge   Solution   Health in Harmony challenge
Week 39: Challenge   Solution   C&BS Co: Web Analytics
Week 40: Challenge   Solution   Sudzilla Conference Survey results
Week 41: Challenge   Solution   C&BS Co: Complaints and Returns
Week 42: Challenge   Solution   C&BS Co: International Expansion
Week 43: Challenge   Solution   C&BS Co: End of Year Store Targets
Week 44: Challenge   Solution   C&BS Co: End of Year Team Member Performance
Week 45: Challenge   Solution   C&BS Co: Duplication and So, So Many Files
Week 46: Challenge   Solution   Naughty & Nice List