Intermediate recap
Nice work — here's everything you just learned.
A quick reference for every concept from the Intermediate track, Cases 21–35.
What you've learned
Window Functions
- RANK() window functionCase 021: The Leaderboard →
- ROW_NUMBER, PARTITION BY, filtering a window resultCase 022: The Latest Order →
- LAG() and LEAD()Case 023: Before and After →
- SUM() OVER (window running total)Case 024: The Running Total →
- RANK vs DENSE_RANK vs ROW_NUMBERCase 025: The Tie Breaker →
Self-Joins & CTEs
- Self-JOINCase 026: Bought Together →
- INTERSECT (set operations)Case 027: Bought Both →
- CTE (WITH clause)Case 028: The High-Value Customers →
- CTE + ROW_NUMBERCase 029: The Second Order →
- Cohort grouping by signup periodCase 030: Signup Cohorts →
- Retention (cohort + follow-up activity)Case 031: Did They Come Back? →
Business Calculations
- Conditional aggregation (SUM + CASE)Case 032: Paid vs. Unpaid →
- Calculated columns, ROUNDCase 033: Profit Margin →
- LEFT JOIN + COALESCECase 034: At-Risk Stock →
- Date arithmetic with DATEDIFF()Case 035: The Churn Signal →
Thirty-five cases down, fifteen to go. Window functions, CTEs, self-joins, real business math — this is the stuff that trips a lot of people up, and you worked through every case of it. What's left is where it all comes together. You've earned the right to feel confident walking in.