SQLiteracy · Intermediate course · Plus
The fact table awakens: joins across a real star schema, aggregation, and the honest truth about NULL.
The Basic course kept you on one table. This one hands you the fact table: hundreds of thousands of rows of monthly airline traffic, joined to airports, carriers, and aircraft. These are the modules where SQL starts doing analysis. And when AI-assisted hints arrive for Pro subscribers, this is where they'll shine.
This course ships with Plus, alongside the full course library. Browse the modules freely; the labs unlock when you upgrade.
Module 1 · ~22 min
Joins across the star
The fact table arrives, and tables start working together
Module 2 · ~20 min
Aggregation
GROUP BY, HAVING, and the one metric every airline watches
Module 3 · ~16 min
NULL but not void
Missing values in filters, aggregates, and this database's own design
Module 4 · ~20 min
CASE and the edge cases
Conditional logic, divide-by-zero guards, and the planes with no passengers
Module 5 · ~20 min
LEFT JOIN and what's missing
Anti-joins, unmatched keys, and the airports the fact table has never met
Finished the modules? Take the final exam: five fresh questions, no hints, and the SQLiteracy Intermediate badge when you pass them all.
Start the examWondering what you've actually learned? Review your skills across every course.
Data: OurAirports (public domain) and U.S. Bureau of Transportation Statistics, T-100 Segment (public domain). Refreshed monthly.