Question

I’m having some trouble writing the SQL statement for the following request: “Find the actors that acted in the movie and in the remake of that same movie”.

The three tables are ‘films’, ‘remakes’ and ‘casts’:
films attributes: filmid, filmname, year, director
remakes attributes: filmid, title, year, priorfilm, priortitle, prioryear
casts attributes: filmid, filmname, actor

So far I know that the priorfilm attribute should correspond with the filmid of the film being tested so I started with this:

select actor
from casts, remakes, actors
where casts.filmid = remakes.priorfilm

But I have no clue how I should proceed with this.

Answer 1

It was a bit confusing, as you had an ‘actor’ table in your SQL, which was not in the three zyou specified…

Try:

select c.actor
from casts c, 
join films f on c.filmid = f.filmid
join remakes r on r.priorfilm = f.filmid
join casts c2 on c.actor = c2.actor and r.filmid = c2.filmid

Note that the casts table has to be joined in two times.