Combining joins with GROUP BY creates aggregated reports across related tables. Join first to combine data, then GROUP BY to aggregate.

Execution order: FROM/JOIN → WHERE → GROUP BY → HAVING → SELECT → ORDER BY. Join creates combined dataset, GROUP BY aggregates it. Use COUNT(column) not COUNT(*) with LEFT JOIN.

Join-aggregate queries power dashboards, reports, and analytics. Understanding how to combine joins with GROUP BY is essential for data analysis roles.

Every business report combines joins and aggregations: customer order counts, product sales totals, employee performance metrics, department budgets. This is the foundation of analytics.