Mastering Your Data with SQL
Like Duolingo, but for Mastering Your Data with SQL. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
Free during early access · No credit card · iPhone & Android
Key ideas in Mastering Your Data with SQL
- Declarative languages focus on the 'what' (the result)
- The FROM clause identifies the source table
- Imperative languages focus on the 'how' (the steps)
- Declarative vs Imperative
- The FROM clause is mandatory for retrieving table data
- The asterisk (*) is the wildcard for all columns
- Queries fail if column names are guessed incorrectly
- The fundamental difference between declarative and imperative programming
- The wildcard saves time when you don't need specific columns
- Table structure (schema) dictates what questions can be asked
- Identifying the keyword used to specify the data source
- The database returns an error if the table name is wrong
- The database does not create tables automatically on request
- SELECT comes before FROM in syntax
- The shorthand syntax for selecting all columns
- The table name follows the FROM keyword
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Mastering Your Data with SQL the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
When you use a declarative language like SQL, what are you actually telling the computer?
Get it right to open this lesson and 219 more in the app.
Where Mastering Your Data with SQL takes you
Stop digging through spreadsheets and start asking your data direct questions. Learn to find, filter, and organize information like a pro using the world's most powerful data language.
- 1
Get Your First Answers
- Asking for what you want
- Looking at specific columns
- Giving your columns better names
- Limiting the number of results
- 2
Finding Exactly What You Need
- Filtering with simple rules
- Using math to find ranges
- Searching for text patterns
- Checking for missing information
- Combining multiple rules at once
- Excluding the things you don't want
- 3
Organizing and Cleaning Your Results
- Sorting from A to Z
- Handling ties in your sorting
- Removing duplicate rows
- 4
Summarizing Big Data
- Counting your items
- Finding totals and averages
- Picking out the highs and lows
- Grouping items into categories
- Filtering your groups
- 5
Connecting Different Data Sources
- The secret to why data is split up
- Matching rows between two tables
- Keeping data even when there is no match
- Joining more than two tables
- 6
Smart Data Transformations
- Doing math across columns
- Creating 'If-Then' logic in your results
- Cleaning up messy text
- Working with dates and times
- Changing data types on the fly
- 7
Advanced Questioning Techniques
- Putting a query inside another query
- Using temporary result sets
- Comparing a row to the one before it
- Ranking your data
- 8
Building and Changing Databases
- Creating your own tables
- Adding new rows of data
- Updating existing information
- Deleting what you don't need
- Changing the structure of a table
- Setting rules to keep data clean
- 9
Speed and Performance
- Why some queries are slow
- Using indexes to speed things up
- Reading an execution plan
- 10
The Engine Under the Hood
- How the database actually reads your code
- The history of the SQL standard
- Differences between MySQL, Postgres, and others
- Designing a perfect database from scratch
10 sections · 44 units · 220 levels. Built to play, not to enroll.
You pick the voice
Mastering Your Data with SQL is taught in the Explain Like I'm 5 style: no big words. promise.. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
More Technology on Tomo
Mastering Maps with QGIS
Stop just looking at maps and start building them. Learn to track weather patterns, analyze local changes, and solve real-world problems using the world's most powerful free mapping tool.
Build Your First Python Apps
Stop reading about code and start writing it. Learn to automate boring tasks and build real tools using the world's most popular programming language.
Build Your Own Home Lab
Move beyond basic Wi-Fi and start building professional-grade networks on your laptop. Learn to architect virtual environments, secure traffic with firewalls, and master the protocols that power the global internet.
Mastering the AI Revolution
Go from curious observer to AI power user. Learn to write perfect prompts, automate your daily tasks, and understand the magic happening behind the screen.
Mastering the Modern Network
Go beyond just connecting to Wi-Fi. Learn to troubleshoot your home setup, protect your personal data from hackers, and master the invisible systems that power the global internet.
Build Your First Game with Godot
Stop dreaming and start building. Learn to create playable games from scratch using the world's most friendly open-source engine.
Start Mastering Your Data with SQL today.
Download Tomo, search Mastering Your Data with SQL, and play your first lesson in under a minute.