can someone explain the difference between using IN and "="? Here is my code. When I use IN it runs perfectly but when I use "=" there is no output. Thank you!
SELECT title FROM movies JOIN stars ON stars.movie_id = movies.id JOIN people ON stars.person_id = people.id WHERE (name = 'Johnny Depp' and movie_id IN ( SELECT movie_id FROM stars JOIN people ON people.id = stars.person_id where name = 'Helena Bonham Carter'))