You now understand when to collapse data with GROUP BY vs preserve detail with window functions, essential for choosing the right analytical approach.

Create summary report with GROUP BY

Add aggregate context to detail rows with OVER

Compare output of same calculation with both approaches

Identify when to use each in real scenarios

Practice combining both with subqueries/CTEs

You have completed the Aggregate Functions & Grouping module! Next, explore Window Functions module for advanced analytical capabilities like ROW_NUMBER, RANK, and running totals.