Students and Subjects tables to create all possible combinations of students and subjects.Examinations table by student_id and subject_name and count the occurrences to get the number of attended exams.student_id and subject_name as keys.IFNULL or a similar function to replace null values in the attended_exams column with zero.student_id and subject_name.erDiagram
Students {
int student_id PK
varchar student_name
}
Subjects {
varchar subject_name PK
}
Examinations {
int student_id
varchar subject_name
}