Hier meiner Meinung nach die Lösung
create database genre;
use genre;
create table tabelle1 (id integer not null, genrename varchar(30),primary key(id));
create table tabelle2 (genreid integer not null, filmid integer not null,primary key(filmid,genreid));
create table tabelle3 (id integer not null, filmname varchar(39) , primary key(id));
insert into tabelle1(id,genrename) values ( 1,'genre1');
insert into tabelle1(id,genrename) values ( 2,'genre2');
insert into tabelle1(id,genrename) values ( 3,'genre3');
insert into tabelle1(id,genrename) values ( 4,'genre4');
insert into tabelle1(id,genrename) values ( 5,'genre5');
insert into tabelle1(id,genrename) values ( 6,'genre6');
insert into tabelle3(id,filmname) values ( 1,'film1');
insert into tabelle3(id,filmname) values ( 2,'film2');
insert into tabelle3(id,filmname) values ( 3,'film3');
insert into tabelle3(id,filmname) values ( 4,'film4');
insert into tabelle3(id,filmname) values ( 5,'film5');
insert into tabelle3(id,filmname) values ( 6,'film6');
insert into tabelle2(filmid,genreid) values ( 1,1);
insert into tabelle2(filmid,genreid) values ( 1,2);
insert into tabelle2(filmid,genreid) values ( 1,3);
insert into tabelle2(filmid,genreid) values ( 1,6);
insert into tabelle2(filmid,genreid) values ( 4,1);
insert into tabelle2(filmid,genreid) values ( 4,2);
insert into tabelle2(filmid,genreid) values ( 4,3);
insert into tabelle2(filmid,genreid) values ( 4,6);
insert into tabelle2(filmid,genreid) values ( 6,6);
select tabelle1.id, tabelle1.genrename , if (tabelle3.id is null,'--','X') as isset
from tabelle1 left outer join tabelle2 on ( tabelle2.genreid = tabelle1.id and tabelle2.filmid = 6)
left outer join tabelle3 on ( tabelle3.id = tabelle2.filmid )
select tabelle1.id, tabelle1.genrename , if (tabelle3.id is null,'--','X') as isset
from tabelle1 left outer join tabelle2 on ( tabelle2.genreid = tabelle1.id and tabelle2.filmid = 4)
left outer join tabelle3 on ( tabelle3.id = tabelle2.filmid )
select tabelle1.id, tabelle1.genrename , if (tabelle3.id is null,'--','X') as isset
from tabelle1 left outer join tabelle2 on ( tabelle2.genreid = tabelle1.id and tabelle2.filmid = 1)
left outer join tabelle3 on ( tabelle3.id = tabelle2.filmid )
select tabelle1.id, tabelle1.genrename , if (tabelle3.id is null,'--','X') as isset
from tabelle1 left outer join tabelle2 on ( tabelle2.genreid = tabelle1.id and tabelle2.filmid = 2)
left outer join tabelle3 on ( tabelle3.id = tabelle2.filmid )