Question

I’m having a little trouble with a query.

I’m building a movie database, It has 3 tables. 1 for movies (tblmovie), 1 for genres (tblgenre), and 1 to connect these 2(tblmoviegenre).

I join these 3 together, so that if I had 3 movies with 3 genre’s each, I would get 9 rows.

Now I would like to be able to get a movie that contains certain genre’s ( for example the one’s with ID 2 and 4), this only works when I do this with one genre, because each row only has 1 genre. Anybody know a work around for this?

So if I try

SELECT tblmovie.name as moviename 
FROM tblmovie as m
LEFT JOIN tblmoviegenre as mg
on m.movieID = mg.movieID
LEFT JOIN tblgenre as g
on mg.genreID = g.genreID
WHERE mg.genreID = 2 
AND mg.genreID = 4

I get no results, because each row only has 1 genre.

Answer 1

try something like this,

SELECT  movieName
FROM    tableName a       -- of course you need to provide joins here
WHERE   genreID IN (2,4)
GROUP BY movieName
HAVING COUNT(*) = 2

The idea here is to match the number of instances to the total number of genre you have provided.

UPDATE 1

SELECT tblmovie.name as moviename 
FROM tblmovie as m
          LEFT JOIN tblmoviegenre as mg
               on m.movieID = mg.movieID
          LEFT JOIN tblgenre as g
               on mg.genreID = g.genreID
WHERE mg.genreID IN (2,4) 
GROUP BY tblmovie.name
HAVING COUNT(*) = 2