Combine joins with GROUP BY for aggregated reports

Use COUNT, SUM, AVG with joined tables

Handle NULL in aggregations with LEFT JOIN

Avoid double-counting with proper grouping

Use HAVING with joined aggregates

Optimize join-aggregate queries

Combine joins with GROUP BY for aggregated reports

Use COUNT, SUM, AVG with joined tables

Handle NULL in aggregations with LEFT JOIN

Avoid double-counting with proper grouping

Use HAVING with joined aggregates

Optimize join-aggregate queries