I have 3 tables (users, courses, messages) and I want to get the last message for each course of a specific user.
users table (id, username, password, phone_number, ...) courses table (id, name, type, author_id, ...) messages table (id, course_id, from, date_created)
messages table includes phone number of user instead of user id so its connection is:
WHERE M.from = (SELECT U.phone_number FROM user U WHERE id=244)
