You can now create hierarchical reports with subtotals and grand totals using ROLLUP, CUBE, and GROUPING SETS for sophisticated multi-level analysis.

Create sales report with ROLLUP for region→country→city

Use CUBE for multi-dimensional product×region analysis

Apply GROUPING() to label subtotal rows

Build custom combinations with GROUPING SETS

Compare ROLLUP vs CUBE output differences

Aggregate Performance Optimization will teach you to optimize complex aggregate queries, use indexes effectively, and design efficient reporting systems.