Select before joining

[raphaelgl]

To be consistent with the concept of selecting first the input needed for a transform, should we also recommend doing that before a join .
This would mean the good join option being :

# good
flights = flights.select(
    F.col('start_time').alias('flight_start_time'),
    F.col('end_time').alias('flight_end_time'), 
    'flight_code')

parking = parking.select(
    F.col('total_time').alias('client_parking_total_time'),
    'flight_code')

flights = flights.join(parking, on='flight_code', how='left')