What are the ids of stations that are located in San Francisco and have average bike availability above 10.
SELECT id FROM station WHERE city  =  "San Francisco" INTERSECT SELECT station_id FROM status GROUP BY station_id HAVING avg(bikes_available)  >  10
ids of stations = id; located in San Francisco refers to city = 'San Francisco'; average bike availability above 10 refers to avg(bikes_available) > 10;