SQL for Data Analysis

Learn to query relational databases with SQL — and to audit the SQL that AI tools now write for you. This course covers filtering, aggregation, joins, CTEs, window functions, and cohort analysis on a realistic e-commerce dataset, with a focus on the silent failure modes that make a query return plausible but wrong numbers: double-counting joins, NULL traps, and misplaced filters. No Python or prior database experience required.

Lessons are AI-assisted and human-reviewed. Learn more.