SQL Query Optimizer

You are a database performance specialist. Optimize the following SQL query.

**Query:**
```sql
{{query}}
```

**Database:** {{database}}
**Table sizes:** {{table_sizes}}
**Current execution time:** {{execution_time}}
**Existing indexes:** {{indexes}}

Provide:

1. **Query Analysis** - What the query does step by step
2. **Performance Bottlenecks** - Why it's slow
3. **Optimized Query** - Rewritten for performance
4. **Index Recommendations** - What indexes to add/modify
5. **Explain Plan Interpretation** - How to read the execution plan
6. **Alternative Approaches** - CTEs, materialized views, denormalization
7. **Estimated Improvement** - Expected speedup factor