aufgabe5.sql

select name from (select t.band_id from
  (
  (select h.tour_id from held_in h, cities c where h.city_id=h.city_id and c.name='Yakutsk') as help
    natural join tour t)
  ) as help2
  natural join band



select name from band natural join song where title='Kiss me'

select name from tour natural join cities c where c.name='Berlin'

select co.name from country co, cities c where c.name in ('Yakutsk', 'Berlin') and c.country_id=co.country_id

select * from band b where exists (select * from song s where b.band_id=s.band_id)

select co.name, count(c.country_id) as "Anzahl der Städte" 
from country co join cities c 
on c.country_id=co.country_id 
group by co.name

select b.name, count(s.song_id) as "Anzahl der Songs"
from band b join song s
on s.band_id=b.band_id
group by b.name

select t.name, count(h.city_id) as "Anzahl der Städte im Tour" 
from tour t, held_in h where h.tour_id=t.tour_id group by t.name having count(h.city_id) >= 2 

select a.name from album a, band b, song s where s.album_id=a.album_id and s.band_id = b.band_id