Context: CREATE TABLE station (name VARCHAR, long VARCHAR, id VARCHAR); CREATE TABLE trip (duration INTEGER, start_station_id VARCHAR)
Question: For each station, return its longitude and the average duration of trips that started from the station.
Answer: SELECT T1.name, T1.long, AVG(T2.duration) FROM station AS T1 JOIN trip AS T2 ON T1.id = T2.start_station_id GROUP BY T2.start_station_id