select id_estacion, extract(month from periodo) as mes, sum(salidas) as total_salidas, sum(llegadas) as total_llegadas from stg_uso group by id_estacion, extract(month from periodo)
select id_estacion, extract(month from periodo) as mes, sum(salidas) as total_salidas, sum(llegadas) as total_llegadas from stg_uso group by id_estacion, extract(month from periodo)