JpaRepository find by manyToMany attribute - spring

Question

Let's imagine classic example of manyToMany relation. I have entities Student and Course and manyToMany relation table between those two entities.
#Entity
data class Student(
#Id
val id: UUID,
val name: String,
#ManyToMany
val courses: Set<Course>
)
#Entity
data class Course(
#Id
val id: UUID,
val title: String,
#ManyToMany
val students: Set<Student>
)
repository can looks like this:
#Repository
interface StudentRepository : JpaRepository<Student, UUID> {
fun findAllByCoursesTitle(title: String): List<Student>
}
Function findAllByCoursesTitle should return all student signed up for math, for example.
My problem is:
How will function looks like when i need to return all students signed up for two specific courses. But i need it for dynamic number of courses, 1 or more.
for example input to function would looks like listOf("math", "geography") or in case of course_ids listOf("UUID", "UUID"). It does not matter if it will be ID or title. What is doalbe.
When i would want to write sql query for that it would looks like this:
SELECT student.id, sc1.course_id, sc2.course_id FROM student
JOIN student_course cs1
ON student.id = cs1.student_id
JOIN student_course cs2
ON student.id = cs2.student_id
WHERE cs1.course_id = ?
AND cs2.course_id = ?
But as i said, i need to have it done for various number of courses.
Please somebody advise.

Answer 1

If you want to resolve logic at SQL statement you can try something like this:
SELECT st.id, sc.course_id, sc.course_id FROM student as st
JOIN (
SELECT st.id as stId, sum(case when c.id IN (:courseIdList) then 1 else 0 end) as cc FROM student as std
JOIN student_course as cs ON std.id = cs.student_id
JOIN cource as c ON c.id = cs.cource_id
GROUP BY (st.id) having cc >= :minimumCourseNumbers
) A on A.stId = st.id
There're courseIdList: List course Ids. minimumCourseNumbers: Minimum course numbers that student must register.
However, I think the logic should move to application to filter.