Rolling Average for Machine Logs

Given a table of manufacturing machine logs, write a query to calculate the rolling average of machine temperature over a three-hour window.

Use the timestamp for each reading and calculate the window separately for each machine. Include readings exactly three hours before the current reading, ignore NULL temperatures in the average, and round the result to two decimal places.

Output

1. One row per machine log, with machine_id, logged_at, temperature_celsius, and rolling_avg_temperature.
2. Include all logs and order by machine_id, logged_at, and log_id.