mysql using subquery with no join

Question

here are the relevant tables

movie(id, title, relYear, category, runTime, director,
studioName, description, rating)

actor(aID, fName, surname, gender)

stars(movieID, actorID)

movGenre(movieID, genre) 

I'm just trying to return movies where 'Michael Fassbender' stars using a subquery ... 'id' in movie refers to the the movie id not the actor id if that was the case I could do

SELECT title, category
FROM movie 
WHERE 'id' =(SELECT 'aID'
             FROM actor
             WHERE fName='Michael' and surname='Fassbender')

Is there a way to do it without using any joins?

Answer 1

You can utilize Correlated Subquery with Exists()

SELECT m.title, m.category
FROM movie AS m
WHERE EXISTS (SELECT 1
              FROM stars AS s 
              JOIN actor AS a ON a.aID = s.actorID
              WHERE a.fName = 'Michael' AND 
                    a.surname = 'Fassbender' AND
                    s.movieID = m.id)

---

Above solution still utilize JOIN in some way (inside the subquery). A solution utilizing no Join at all can be:

SELECT title, category
FROM movie
WHERE id IN (SELECT movieID 
             FROM stars 
             WHERE actorID IN (SELECT aID 
                               FROM actor 
                               WHERE fName = 'Michael' AND 
                                     surname = 'Fassbender'))

PS Unless this is some trick assignment/HW, I would seriously recommend against using this query in a real-life application.

Answer 2

SELECT DISTINCT m.title, m.category
FROM movie 
INNER JOIN stars s
ON s.movieID = m.id
INNER JOIN actors a
ON s.actorID = a.aID
   AND a.fName='Michael' 
   AND a.surname='Fassbender'