DELETE From BookINGS 
 USING BOOKINGS JOIN SESSIONS JOIN COURSES
 WHERE BOOKINGS.session_id = SESSIONS.session_id
   AND SESSIONS.course_id = COURSES.course_id
   AND COURSES.course_id = ?

另一种方法是使用stored procedure,并按正确的顺序处理删除：

>预订

DELETE From BOOKINGS
 WHERE EXISTS(SELECT NULL
                FROM SESSIONS s 
               WHERE s.session_id = session_id
                 AND s.course_id = ?)

>会话

DELETE FROM SESSIONS
 WHERE EXISTS(SELECT NULL
                FROM COURSES c
               WHERE c.course_id = course_id
                 AND c.course_id = ?)

>课程

DELETE FROM COURSES
 WHERE course_id = ?