Hier werden die Beispielqueries aus der Fragestunde (1.2.) zugreifbar gemacht.

select country.code, country.name
from city, country
where city.population > 1000000
  and country.code = city.country

select code, name
from country
where not exists 
(  select *
   from city
   where population > 1000000
     and country.code = city.country
)

select name
from island
where not exists
  (select *
   from locatedon
   where locatedon.island = island.name)

select * from organization where abbreviation = 'Benelux'

select * 
from ismember
where organization = 'Benelux'

select * 
from organization o
where not exists
(select country
 from ismember i1
 where organization = 'Benelux'
   and not exists
    (select *
     from ismember i2
     where i1.country=i2.country
       and i2.organization = o.abbreviation))