Oracle 11g Release 2

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create table students (student_id integer, student_name varchar(100));
insert into students(student_id,student_name)
select 1, 'Alice' from dual
union all
select 2, 'Bob' from dual
union all
select 3, 'Charlie' from dual;
3 rows affected

create table courses (course_id integer, professor_id integer);
insert into courses
select 9+level, mod(level,3)+101 from dual connect by level<=10;
10 rows affected

create table takes_courses (student_id integer, course_id integer);
insert into takes_courses
select student_id, course_id
from students cross join courses
where course_id<10+student_id*3;
18 rows affected

select student_name
from students
where student_id in ( select student_id
                      from( select distinct student_id, professor_id, course_id
                            from takes_courses join courses using(course_id) )
                      group by student_id, professor_id
                      having count(*)>1 );


STUDENT_NAME


Bob

Charlie