Users based on ep_course table

The ep_course table user list is more accurate than the other tables, but the result is an array in a field. How can I separate the field into a student_user_id column?

SQL

USE arwiki_p; #set the language/project

# SELECT user_name, user_id from user WHERE user_name = 'Reem Al-Kashif'; #This user should be in all 3 courses

# SELECT * from ep_students WHERE student_user_id = 552387 GROUP BY student_first_course;

#student user table
SELECT COUNT(student_user_id) from ep_students
WHERE student_first_course = IN (2,56,63)
GROUP BY student_first_course
#course table
SELECT course_id, course_start, course_End, course_students FROM ep_courses
WHERE course_id IN (2,56,63); #IN allows you to specify multiple course IDs*/

SQL

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