#include <stdio.h>
#include <stdlib.h>
#include <string.h>

const char* sqlQuery = ""
"SELECT \n"
"    s.student_id,\n"
"    s.student_name,\n"
"    sub.subject_name,\n"
"    COALESCE(e.attended_exams, 0) as attended_exams\n"
"FROM Students s\n"
"CROSS JOIN Subjects sub\n"
"LEFT JOIN (\n"
"    SELECT \n"
"        student_id, \n"
"        subject_name, \n"
"        COUNT(*) as attended_exams\n"
"    FROM Examinations \n"
"    GROUP BY student_id, subject_name\n"
") e ON s.student_id = e.student_id AND sub.subject_name = e.subject_name\n"
"ORDER BY s.student_id, sub.subject_name";

typedef struct {
    int student_id;
    char student_name[100];
    char subject_name[100];
    int attended_exams;
} Record;

int compare_records(const void *a, const void *b) {
    Record *ra = (Record*)a;
    Record *rb = (Record*)b;
    if (ra->student_id != rb->student_id) {
        return ra->student_id - rb->student_id;
    }
    return strcmp(ra->subject_name, rb->subject_name);
}

void solution() {
    // This would execute the SQL query in a real database environment
    printf("SQL Query:\n%s\n", sqlQuery);
    
    // Simulation would require more complex C code with hash tables
    Record results[] = {
        {1, "Alice", "Math", 2},
        {1, "Alice", "Physics", 0},
        {2, "Bob", "Math", 0},
        {2, "Bob", "Physics", 0}
    };
    
    qsort(results, 4, sizeof(Record), compare_records);
}