Question: Show the station name with greatest number of trains.
Schema: create table station (name varchar, station_id varchar, PRIMARY KEY (name)); create table train_station (station_id varchar, PRIMARY KEY (station_id))
SQL: select t2.name from train_station as t1 join station as t2 on t1.station_id = t2.station_id group by t1.station_id order by count(*) desc limit 1