I need to know which train route passes through the most stations, please.
select t1.name from train as t1 join route as t2 on t1.id = t2.train_id group by t2.train_id order by count ( * ) desc limit 1
How many stations does this train run through?
select count ( * ) from train as t1 join route as t2 on t1.id = t2.train_id group by t2.train_id order by count ( * ) desc limit 1
What are the names of those stations?
select t2.station_id from train as t1 join route as t2 on t1.id = t2.train_id group by t2.train_id order by count ( * ) desc limit 3