List name of ships?
select name from ship
Show flags of ships?
select name, flag from ship
Name of ships not steered by by any captain with Midshipman rank?
select name from ship where ship_id not in ( select ship_id from captain where rank = 'Midshipman' )
Flags of ships not steered by any captain with Midshipman rank?
select flag from ship where ship_id not in ( select ship_id from captain where rank = 'Midshipman' )
Okay. Name and flags of ships not steered by any captain of Midshipman rank?
select name, flag from ship where ship_id not in ( select ship_id from captain where rank = 'Midshipman' )