Average Delay per Route

Return each route and the average departure delay in minutes (early departures count as negative), rounded to 2 decimals. Order by route.

Table schema

Flights(id INT PRIMARY KEY, route VARCHAR(10), scheduled_dep DATETIME, actual_dep DATETIME, seats INT, booked INT)

Sample data

id | route | scheduled_dep | actual_dep | seats | booked
1 | DEL-BOM | 2026-05-01 08:00:00 | 2026-05-01 08:20:00 | 180 | 150
2 | DEL-BOM | 2026-05-02 08:00:00 | 2026-05-02 08:00:00 | 180 | 170
3 | BOM-BLR | 2026-05-01 10:00:00 | 2026-05-01 10:45:00 | 150 | 90
4 | BOM-BLR | 2026-05-02 10:00:00 | 2026-05-02 09:55:00 | 150 | 120
5 | DEL-BLR | 2026-05-03 12:00:00 | 2026-05-03 12:30:00 | 200 | 100