Obtenga filas de 1 mesa con otra mesa vacía mysql

SELECT students.name, students.lastname, ifnull(courses.course_name, '-') as course_name
FROM students
LEFT JOIN courses
ON courses.id_student=students.id_student 
WHERE students.name LIKE '%$search%'
GROUP BY students.id_student 
ORDER BY students.name, students.lastname, courses.course_name
Ivan The Terrible