SQL query to find rows with at least one of the specified values - sql

Question

Suppose you had two tables. One called MOVIES:
MovieId
MovieName
Then another called ACTORS that contains people who appear in those movies:
MovieId
ActorName
Now, I want to write a query that returns any movie that contains ONE OR MORE of the following actors: "Tom Hanks", "Russell Crowe" or "Arnold Schwarzenegger".
One way to do it would be something like:
SELECT DISTINCT A.MovieId, M.MovieName FROM ACTORS A
INNER JOIN MOVIES M USING (MovieId)
WHERE A.ActorName IN ('Tom Hanks', 'Russell Crowe', 'Arnold Schwarzenegger');
Which is perfectly fine, however in my case I might have several more of these conditions on the WHERE clause so I want to find a way to make the MOVIES table the primary table I select from.
What's the best way to query for this? I'm using Oracle 11g if that matters, but I'm hoping for a standard SQL method.

Answer 1

You can use EXISTS or IN subqueries:
SELECT *
FROM MOVIES m
WHERE EXISTS
(
SELECT *
FROM ACTORS a
WHERE a.MovieId = m.MovieId
AND a.ActorName IN ('Tom Hanks', 'Russell Crowe', 'Arnold Schwarzenegger')
)
or
SELECT *
FROM MOVIES m
WHERE m.MovieId IN
(
SELECT a.MovieId
FROM ACTORS a
WHERE a.ActorName IN ('Tom Hanks', 'Russell Crowe', 'Arnold Schwarzenegger')
)

Answer 2

First you should have a 3rd table implementing the n:m relationship:
CREATE TABLE movie (
movie_id int primary key
,moviename text
-- more fields
);
CREATE TABLE actor (
actor_id int primary key
,actorname text
-- more fields
);
CREATE TABLE movieactor (
movie_id int references movie(movie_id)
,actor_id int references actor(actor_id)
,CONSTRAINT movieactor_pkey PRIMARY KEY (movie_id, actor_id)
);
Then you select like this:
SELECT DISTINCT m.movie_id, m.moviename
FROM movie m
JOIN movieactor ma USING (movie_id)
JOIN actor a USING (actor_id)
WHERE a.actorname IN ('Tom Hanks', 'Russell Crowe', 'Arnold Schwarzenegger');
Note, that text literals are enclose in single quotes!