Write a SQL query to analyze city-level ride demand, driver supply, and conversion trends over time for Didi Chuxing.
Use the cities, ride_requests, and driver_sessions tables. Report monthly metrics for the available reporting period, excluding requests without a valid city.
Output
- One row per city and month with ride requests, completed rides, active drivers, and conversion rate.
- Columns:
city_name, month, ride_requests, completed_rides, active_drivers, conversion_rate.
- Sort by
city_name, then month ascending.