How to create sql query results in columns from rows?
I don't have the energy to deal with all the joins through all your tables, but the general idea would be to join to the store table twice and check the results.

 SELECT f.film_id,
   CASE when store1.store_id is not null then 'Item exists in store 1' else 'Item missing from store 1' END as 'Store 1 Status'
 FROM film f
 LEFT OUTER JOIN store store1 on f.film_id = store1.film_id AND store1.store_id = 1
 LEFT OUTER JOIN store store2 on f.film_id = store2.film_id AND store2.store_id = 2


This doesn't scale well if you had 100 stores, but for two it wouldn't be evil.

Hope that helps.