diff --git a/submissions/SS/DAHMOUN_Mouaine_Aymen/tp1_solutions.sql b/submissions/SS/DAHMOUN_Mouaine_Aymen/tp1_solutions.sql
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+-- ============================================
+-- TP1: University Management System - Solution
+-- File: tp1_solutions.sql
+-- Created for the assignment requirements
+-- ============================================
+
+-- Create database
+CREATE DATABASE IF NOT EXISTS university_db;
+USE university_db;
+
+-- ========== TABLES ==========
+
+-- 1) departments
+CREATE TABLE IF NOT EXISTS departments (
+    department_id INT AUTO_INCREMENT PRIMARY KEY,
+    department_name VARCHAR(100) NOT NULL,
+    building VARCHAR(50),
+    budget DECIMAL(12,2),
+    department_head VARCHAR(100),
+    creation_date DATE
+) ENGINE=InnoDB;
+
+-- 2) professors
+CREATE TABLE IF NOT EXISTS professors (
+    professor_id INT AUTO_INCREMENT PRIMARY KEY,
+    last_name VARCHAR(50) NOT NULL,
+    first_name VARCHAR(50) NOT NULL,
+    email VARCHAR(100) NOT NULL UNIQUE,
+    phone VARCHAR(20),
+    department_id INT NULL,
+    hire_date DATE,
+    salary DECIMAL(10,2),
+    specialization VARCHAR(100),
+    CONSTRAINT fk_prof_dept FOREIGN KEY (department_id)
+        REFERENCES departments(department_id)
+        ON DELETE SET NULL
+        ON UPDATE CASCADE
+) ENGINE=InnoDB;
+
+-- 3) students
+CREATE TABLE IF NOT EXISTS students (
+    student_id INT AUTO_INCREMENT PRIMARY KEY,
+    student_number VARCHAR(20) NOT NULL UNIQUE,
+    last_name VARCHAR(50) NOT NULL,
+    first_name VARCHAR(50) NOT NULL,
+    date_of_birth DATE,
+    email VARCHAR(100) NOT NULL UNIQUE,
+    phone VARCHAR(20),
+    address TEXT,
+    department_id INT NULL,
+    level VARCHAR(20),
+    enrollment_date DATE DEFAULT (CURRENT_DATE),
+    CONSTRAINT chk_student_level CHECK (level IN ('L1','L2','L3','M1','M2')),
+    CONSTRAINT fk_student_dept FOREIGN KEY (department_id)
+        REFERENCES departments(department_id)
+        ON DELETE SET NULL
+        ON UPDATE CASCADE
+) ENGINE=InnoDB;
+
+-- 4) courses
+CREATE TABLE IF NOT EXISTS courses (
+    course_id INT AUTO_INCREMENT PRIMARY KEY,
+    course_code VARCHAR(10) NOT NULL UNIQUE,
+    course_name VARCHAR(150) NOT NULL,
+    description TEXT,
+    credits INT NOT NULL,
+    semester INT,
+    department_id INT,
+    professor_id INT NULL,
+    max_capacity INT DEFAULT 30,
+    CONSTRAINT chk_credits CHECK (credits > 0),
+    CONSTRAINT chk_semester CHECK (semester BETWEEN 1 AND 2),
+    CONSTRAINT fk_course_dept FOREIGN KEY (department_id)
+        REFERENCES departments(department_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    CONSTRAINT fk_course_prof FOREIGN KEY (professor_id)
+        REFERENCES professors(professor_id)
+        ON DELETE SET NULL
+        ON UPDATE CASCADE
+) ENGINE=InnoDB;
+
+-- 5) enrollments
+CREATE TABLE IF NOT EXISTS enrollments (
+    enrollment_id INT AUTO_INCREMENT PRIMARY KEY,
+    student_id INT NOT NULL,
+    course_id INT NOT NULL,
+    enrollment_date DATE DEFAULT (CURRENT_DATE),
+    academic_year VARCHAR(9) NOT NULL, -- format '2024-2025'
+    status VARCHAR(20) DEFAULT 'In Progress',
+    CONSTRAINT chk_status CHECK (status IN ('In Progress','Passed','Failed','Dropped')),
+    CONSTRAINT fk_enroll_student FOREIGN KEY (student_id)
+        REFERENCES students(student_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    CONSTRAINT fk_enroll_course FOREIGN KEY (course_id)
+        REFERENCES courses(course_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    CONSTRAINT uc_enrollment_unique UNIQUE (student_id, course_id, academic_year)
+) ENGINE=InnoDB;
+
+-- 6) grades
+CREATE TABLE IF NOT EXISTS grades (
+    grade_id INT AUTO_INCREMENT PRIMARY KEY,
+    enrollment_id INT NOT NULL,
+    evaluation_type VARCHAR(30),
+    grade DECIMAL(5,2),
+    coefficient DECIMAL(3,2) DEFAULT 1.00,
+    evaluation_date DATE,
+    comments TEXT,
+    CONSTRAINT chk_eval_type CHECK (evaluation_type IN ('Assignment','Lab','Exam','Project')),
+    CONSTRAINT chk_grade_range CHECK (grade >= 0 AND grade <= 20),
+    CONSTRAINT fk_grade_enrollment FOREIGN KEY (enrollment_id)
+        REFERENCES enrollments(enrollment_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE
+) ENGINE=InnoDB;
+
+-- ========== INDEXES ==========
+
+CREATE INDEX idx_student_department ON students(department_id);
+CREATE INDEX idx_course_professor ON courses(professor_id);
+CREATE INDEX idx_enrollment_student ON enrollments(student_id);
+CREATE INDEX idx_enrollment_course ON enrollments(course_id);
+CREATE INDEX idx_grades_enrollment ON grades(enrollment_id);
+
+-- ========== TEST DATA INSERTION ==========
+
+-- Departments (4)
+INSERT INTO departments (department_name, building, budget, department_head, creation_date) VALUES
+('Computer Science', 'Building A', 500000.00, 'Dr. Alan Turing', '2000-09-01'),
+('Mathematics', 'Building B', 350000.00, 'Dr. Ada Lovelace', '2001-09-01'),
+('Physics', 'Building C', 400000.00, 'Dr. Marie Curie', '2002-09-01'),
+('Civil Engineering', 'Building D', 600000.00, 'Dr. I. K. Brunel', '2003-09-01');
+
+-- Professors (6) - at least 3 in Computer Science
+INSERT INTO professors (last_name, first_name, email, phone, department_id, hire_date, salary, specialization) VALUES
+('Smith','John','john.smith@uni.edu','+213600000001', 1, '2010-08-15', 70000.00, 'Algorithms'),
+('Doe','Jane','jane.doe@uni.edu','+213600000002', 1, '2012-09-01', 65000.00, 'Databases'),
+('Brown','Alice','alice.brown@uni.edu','+213600000003', 1, '2015-01-10', 60000.00, 'Artificial Intelligence'),
+('Green','Bob','bob.green@uni.edu','+213600000004', 2, '2011-07-20', 62000.00, 'Topology'),
+('White','Carol','carol.white@uni.edu','+213600000005', 3, '2013-05-05', 63000.00, 'Quantum Mechanics'),
+('Black','Dave','dave.black@uni.edu','+213600000006', 4, '2009-03-12', 75000.00, 'Structural Engineering');
+
+-- Students (8) - mix of levels, distributed across departments
+INSERT INTO students (student_number, last_name, first_name, date_of_birth, email, phone, address, department_id, level, enrollment_date) VALUES
+('S2024001','Ali','Aymen','2002-05-10','aymen.ali@uni.edu','+213661000001','Addr 1', 1, 'L3', '2023-09-01'),
+('S2024002','Ben','Sara','2003-03-22','sara.ben@uni.edu','+213661000002','Addr 2', 1, 'L2', '2024-09-01'),
+('S2024003','Chen','Lina','2002-11-02','lina.chen@uni.edu','+213661000003','Addr 3', 2, 'L3', '2023-09-01'),
+('S2024004','Diaz','Omar','1998-07-15','omar.diaz@uni.edu','+213661000004','Addr 4', 3, 'M1', '2023-09-01'),
+('S2024005','Elbaz','Maya','2004-02-28','maya.elbaz@uni.edu','+213661000005','Addr 5', 4, 'L2', '2024-09-01'),
+('S2024006','Fares','Nora','1997-12-11','nora.fares@uni.edu','+213661000006','Addr 6', 1, 'M1', '2023-09-01'),
+('S2024007','Garcia','Leo','2003-06-30','leo.garcia@uni.edu','+213661000007','Addr 7', 2, 'L3', '2024-09-01'),
+('S2024008','Hassan','Rima','2004-09-09','rima.hassan@uni.edu','+213661000008','Addr 8', 3, 'L2', '2024-09-01');
+
+-- Courses (7) - various credits, semesters, assigned to professors
+INSERT INTO courses (course_code, course_name, description, credits, semester, department_id, professor_id, max_capacity) VALUES
+('CS101','Intro to Programming','Basics of programming in Python', 6, 1, 1, 1, 40),
+('CS201','Data Structures','In-depth data structures', 6, 2, 1, 2, 35),
+('CS301','Machine Learning','Intro to ML concepts', 6, 1, 1, 3, 30),
+('CS350','Advanced Databases','Distributed DB systems', 5, 2, 1, 2, 30),
+('MATH201','Linear Algebra II','Vector spaces and matrices', 5, 1, 2, 4, 30),
+('PHYS101','Classical Mechanics','Newtonian mechanics', 5, 2, 3, 5, 25),
+('CE101','Statics','Forces and equilibrium', 6, 1, 4, 6, 30);
+
+-- Enrollments (15) - mix of academic years and statuses
+INSERT INTO enrollments (student_id, course_id, enrollment_date, academic_year, status) VALUES
+(1, 1, '2024-09-05', '2024-2025', 'In Progress'),   -- e1
+(1, 2, '2023-09-03', '2023-2024', 'Passed'),        -- e2
+(1, 4, '2024-09-06', '2024-2025', 'In Progress'),   -- e3
+(2, 1, '2024-09-07', '2024-2025', 'In Progress'),   -- e4
+(2, 4, '2024-09-07', '2024-2025', 'In Progress'),   -- e5
+(3, 5, '2023-09-04', '2023-2024', 'Passed'),        -- e6
+(3, 2, '2024-09-05', '2024-2025', 'In Progress'),   -- e7
+(4, 6, '2024-09-02', '2024-2025', 'In Progress'),   -- e8
+(5, 7, '2024-09-03', '2024-2025', 'In Progress'),   -- e9
+(6, 1, '2023-09-03', '2023-2024', 'Failed'),        -- e10
+(6, 3, '2024-09-05', '2024-2025', 'In Progress'),   -- e11
+(7, 5, '2024-09-05', '2024-2025', 'In Progress'),   -- e12
+(8, 6, '2023-09-06', '2023-2024', 'Dropped'),       -- e13
+(4, 3, '2023-09-05', '2023-2024', 'Passed'),        -- e14
+(5, 2, '2023-09-05', '2023-2024', 'Passed');        -- e15
+
+INSERT INTO grades (enrollment_id, evaluation_type, grade, coefficient, evaluation_date, comments) VALUES
+(2, 'Exam', 15.50, 2.00, '2024-01-10', 'Final exam'),     -- grade for e2 (student1, CS201)
+(6, 'Exam', 14.00, 2.00, '2024-01-12', 'Final exam'),     -- e6 (student3, MATH201)
+(10,'Exam', 9.50, 2.00, '2024-01-15','Final exam'),       -- e10 (student6, CS101) -> Failed
+(14,'Exam', 16.00, 2.00, '2024-01-11','Final exam'),      -- e14 (student4, CS301)
+(15,'Exam', 12.50, 2.00, '2024-01-09','Final exam'),      -- e15 (student5, CS201)
+(1, 'Assignment', 17.00, 1.00, '2024-10-20','Good work'), -- e1 (student1, CS101)
+(1, 'Lab', 16.00, 1.00, '2024-11-05','Lab exercises'),    -- e1
+(3, 'Assignment', 13.00, 1.00, '2024-10-25','Ok'),        -- e3
+(4, 'Project', 14.50, 1.50, '2024-11-10','Team project'), -- e4
+(5, 'Assignment', 11.00, 1.00, '2024-11-01','Late'),      -- e5
+(11,'Exam', 18.00, 2.00, '2025-01-15','Excellent'),      -- e11
+(7, 'Lab', 12.00, 1.00, '2024-11-12','Labs');             -- e7
+
+
+
+-- Q1. List all students with their main information (name, email, level)
+-- Expected columns: last_name, first_name, email, level
+SELECT last_name, first_name, email, level
+FROM students
+ORDER BY last_name, first_name;
+
+-- Q2. Display all professors from the Computer Science department
+-- Expected columns: last_name, first_name, email, specialization
+SELECT p.last_name, p.first_name, p.email, p.specialization
+FROM professors p
+JOIN departments d ON p.department_id = d.department_id
+WHERE d.department_name = 'Computer Science';
+
+-- Q3. Find all courses with more than 5 credits
+-- Expected columns: course_code, course_name, credits
+SELECT course_code, course_name, credits
+FROM courses
+WHERE credits > 5;
+
+-- Q4. List students enrolled in L3 level
+-- Expected columns: student_number, last_name, first_name, email
+SELECT student_number, last_name, first_name, email
+FROM students
+WHERE level = 'L3';
+
+-- Q5. Display courses from semester 1
+-- Expected columns: course_code, course_name, credits, semester
+SELECT course_code, course_name, credits, semester
+FROM courses
+WHERE semester = 1;
+
+-- ========== PART 2: QUERIES WITH JOINS (Q6-Q10) ==========
+
+-- Q6. Display all courses with the professor's name
+-- Expected columns: course_code, course_name, professor_name (last + first)
+SELECT c.course_code, c.course_name, 
+       CASE WHEN p.professor_id IS NOT NULL THEN CONCAT(p.last_name, ' ', p.first_name) ELSE 'TBA' END AS professor_name
+FROM courses c
+LEFT JOIN professors p ON c.professor_id = p.professor_id
+ORDER BY c.course_code;
+
+-- Q7. List all enrollments with student name and course name
+-- Expected columns: student_name, course_name, enrollment_date, status
+SELECT CONCAT(s.last_name, ' ', s.first_name) AS student_name,
+       c.course_name,
+       e.enrollment_date,
+       e.status
+FROM enrollments e
+JOIN students s ON e.student_id = s.student_id
+JOIN courses c ON e.course_id = c.course_id
+ORDER BY e.enrollment_date DESC;
+
+-- Q8. Display students with their department name
+-- Expected columns: student_name, department_name, level
+SELECT CONCAT(s.last_name, ' ', s.first_name) AS student_name,
+       d.department_name,
+       s.level
+FROM students s
+LEFT JOIN departments d ON s.department_id = d.department_id
+ORDER BY d.department_name, s.last_name;
+
+-- Q9. List grades with student name, course name, and grade obtained
+-- Expected columns: student_name, course_name, evaluation_type, grade
+SELECT CONCAT(st.last_name,' ',st.first_name) AS student_name,
+       c.course_name,
+       g.evaluation_type,
+       g.grade
+FROM grades g
+JOIN enrollments e ON g.enrollment_id = e.enrollment_id
+JOIN students st ON e.student_id = st.student_id
+JOIN courses c ON e.course_id = c.course_id
+ORDER BY st.last_name, g.evaluation_date;
+
+-- Q10. Display professors with the number of courses they teach
+-- Expected columns: professor_name, number_of_courses
+SELECT CONCAT(p.last_name,' ',p.first_name) AS professor_name,
+       COUNT(c.course_id) AS number_of_courses
+FROM professors p
+LEFT JOIN courses c ON p.professor_id = c.professor_id
+GROUP BY p.professor_id
+ORDER BY number_of_courses DESC;
+
+-- ========== PART 3: AGGREGATE FUNCTIONS (Q11-Q15) ==========
+
+-- Q11. Calculate the overall average grade for each student
+-- Expected columns: student_name, average_grade
+SELECT CONCAT(s.last_name,' ',s.first_name) AS student_name,
+       ROUND(AVG(g.grade),2) AS average_grade
+FROM students s
+JOIN enrollments e ON s.student_id = e.student_id
+JOIN grades g ON e.enrollment_id = g.enrollment_id
+GROUP BY s.student_id
+ORDER BY average_grade DESC;
+
+-- Q12. Count the number of students per department
+-- Expected columns: department_name, student_count
+SELECT d.department_name,
+       COUNT(s.student_id) AS student_count
+FROM departments d
+LEFT JOIN students s ON d.department_id = s.department_id
+GROUP BY d.department_id
+ORDER BY student_count DESC;
+
+-- Q13. Calculate the total budget of all departments
+-- Expected result: One row with total_budget
+SELECT ROUND(SUM(budget),2) AS total_budget
+FROM departments;
+
+-- Q14. Find the total number of courses per department
+-- Expected columns: department_name, course_count
+SELECT d.department_name,
+       COUNT(c.course_id) AS course_count
+FROM departments d
+LEFT JOIN courses c ON d.department_id = c.department_id
+GROUP BY d.department_id
+ORDER BY course_count DESC;
+
+-- Q15. Calculate the average salary of professors per department
+-- Expected columns: department_name, average_salary
+SELECT d.department_name,
+       ROUND(AVG(p.salary),2) AS average_salary
+FROM departments d
+LEFT JOIN professors p ON d.department_id = p.department_id
+GROUP BY d.department_id
+ORDER BY average_salary DESC;
+
+-- ========== PART 4: ADVANCED QUERIES (Q16-Q20) ==========
+
+-- Q16. Find the top 3 students with the best averages
+-- Expected columns: student_name, average_grade (order desc, limit 3)
+SELECT student_name, average_grade
+FROM (
+    SELECT CONCAT(s.last_name,' ',s.first_name) AS student_name,
+           AVG(g.grade) AS average_grade
+    FROM students s
+    JOIN enrollments e ON s.student_id = e.student_id
+    JOIN grades g ON e.enrollment_id = g.enrollment_id
+    GROUP BY s.student_id
+) t
+ORDER BY average_grade DESC
+LIMIT 3;
+
+-- Q17. List courses with no enrolled students
+-- Expected columns: course_code, course_name
+SELECT c.course_code, c.course_name
+FROM courses c
+LEFT JOIN enrollments e ON c.course_id = e.course_id
+WHERE e.enrollment_id IS NULL;
+
+-- Q18. Display students who have passed all their courses (status = 'Passed')
+-- Expected columns: student_name, passed_courses_count
+SELECT CONCAT(s.last_name,' ',s.first_name) AS student_name,
+       COUNT(e.enrollment_id) AS passed_courses_count
+FROM students s
+JOIN enrollments e ON s.student_id = e.student_id
+GROUP BY s.student_id
+HAVING SUM(CASE WHEN e.status = 'Passed' THEN 0 ELSE 1 END) = 0
+   AND COUNT(e.enrollment_id) > 0;
+
+-- Q19. Find professors who teach more than 2 courses
+-- Expected columns: professor_name, courses_taught
+SELECT CONCAT(p.last_name,' ',p.first_name) AS professor_name,
+       COUNT(c.course_id) AS courses_taught
+FROM professors p
+JOIN courses c ON p.professor_id = c.professor_id
+GROUP BY p.professor_id
+HAVING COUNT(c.course_id) > 2;
+
+-- Q20. List students enrolled in more than 2 courses
+-- Expected columns: student_name, enrolled_courses_count
+SELECT CONCAT(s.last_name,' ',s.first_name) AS student_name,
+       COUNT(e.enrollment_id) AS enrolled_courses_count
+FROM students s
+JOIN enrollments e ON s.student_id = e.student_id
+GROUP BY s.student_id
+HAVING COUNT(e.enrollment_id) > 2;
+
+-- ========== PART 5: SUBQUERIES (Q21-Q25) ==========
+
+-- Q21. Find students with an average higher than their department's average
+-- Expected columns: student_name, student_avg, department_avg
+SELECT t.student_name, ROUND(t.student_avg,2) AS student_avg, ROUND(d.department_avg,2) AS department_avg
+FROM (
+    SELECT s.student_id, CONCAT(s.last_name,' ',s.first_name) AS student_name,
+           AVG(g.grade) AS student_avg, s.department_id
+    FROM students s
+    JOIN enrollments e ON s.student_id = e.student_id
+    JOIN grades g ON e.enrollment_id = g.enrollment_id
+    GROUP BY s.student_id
+) t
+JOIN (
+    SELECT s.department_id, AVG(g.grade) AS department_avg
+    FROM students s
+    JOIN enrollments e ON s.student_id = e.student_id
+    JOIN grades g ON e.enrollment_id = g.enrollment_id
+    GROUP BY s.department_id
+) d ON t.department_id = d.department_id
+WHERE t.student_avg > d.department_avg
+ORDER BY (t.student_avg - d.department_avg) DESC;
+
+-- Q22. List courses with more enrollments than the average number of enrollments
+-- Expected columns: course_name, enrollment_count
+SELECT course_name, enrollment_count
+FROM (
+    SELECT c.course_id, c.course_name, COUNT(e.enrollment_id) AS enrollment_count
+    FROM courses c
+    LEFT JOIN enrollments e ON c.course_id = e.course_id
+    GROUP BY c.course_id
+) cc
+WHERE enrollment_count > (
+    SELECT AVG(cnt) FROM (
+        SELECT COUNT(*) AS cnt FROM enrollments GROUP BY course_id
+    ) sub
+);
+
+-- Q23. Display professors from the department with the highest budget
+-- Expected columns: professor_name, department_name, budget
+SELECT CONCAT(p.last_name,' ',p.first_name) AS professor_name,
+       d.department_name, d.budget
+FROM professors p
+JOIN departments d ON p.department_id = d.department_id
+WHERE d.budget = (SELECT MAX(budget) FROM departments);
+
+-- Q24. Find students with no grades recorded
+-- Expected columns: student_name, email
+SELECT CONCAT(s.last_name,' ',s.first_name) AS student_name, s.email
+FROM students s
+WHERE NOT EXISTS (
+    SELECT 1 FROM enrollments e
+    JOIN grades g ON e.enrollment_id = g.enrollment_id
+    WHERE e.student_id = s.student_id
+);
+
+-- Q25. List departments with more students than the average
+-- Expected columns: department_name, student_count
+SELECT d.department_name, dept_count.student_count
+FROM departments d
+JOIN (
+    SELECT s.department_id, COUNT(s.student_id) AS student_count
+    FROM students s
+    GROUP BY s.department_id
+) dept_count ON d.department_id = dept_count.department_id
+WHERE dept_count.student_count > (
+    SELECT AVG(cnt) FROM (
+        SELECT COUNT(*) AS cnt FROM students GROUP BY department_id
+    ) sub_avg
+)
+ORDER BY dept_count.student_count DESC;
+
+-- ========== PART 6: BUSINESS ANALYSIS (Q26-Q30) ==========
+
+-- Q26. Calculate the pass rate per course (grades >= 10/20)
+-- Expected columns: course_name, total_grades, passed_grades, pass_rate_percentage
+SELECT c.course_name,
+       COUNT(g.grade_id) AS total_grades,
+       SUM(CASE WHEN g.grade >= 10 THEN 1 ELSE 0 END) AS passed_grades,
+       ROUND(100.0 * SUM(CASE WHEN g.grade >= 10 THEN 1 ELSE 0 END) / NULLIF(COUNT(g.grade_id),0),2) AS pass_rate_percentage
+FROM courses c
+LEFT JOIN enrollments e ON c.course_id = e.course_id
+LEFT JOIN grades g ON e.enrollment_id = g.enrollment_id
+GROUP BY c.course_id
+ORDER BY pass_rate_percentage DESC;
+
+-- Q27. Display student ranking by descending average
+-- Expected columns: rank, student_name, average_grade
+-- Using window function to rank (MySQL 8+)
+WITH student_avgs AS (
+    SELECT s.student_id, CONCAT(s.last_name,' ',s.first_name) AS student_name,
+           ROUND(AVG(g.grade),2) AS average_grade
+    FROM students s
+    JOIN enrollments e ON s.student_id = e.student_id
+    JOIN grades g ON e.enrollment_id = g.enrollment_id
+    GROUP BY s.student_id
+)
+SELECT RANK() OVER (ORDER BY average_grade DESC) AS rank,
+       student_name,
+       average_grade
+FROM student_avgs
+ORDER BY rank;
+
+-- Q28. Generate a report card for student with student_id = 1
+-- Expected columns: course_name, evaluation_type, grade, coefficient, weighted_grade
+SELECT c.course_name,
+       g.evaluation_type,
+       g.grade,
+       g.coefficient,
+       ROUND(g.grade * g.coefficient,2) AS weighted_grade
+FROM grades g
+JOIN enrollments e ON g.enrollment_id = e.enrollment_id
+JOIN courses c ON e.course_id = c.course_id
+WHERE e.student_id = 1
+ORDER BY c.course_name, g.evaluation_date;
+
+-- Q29. Calculate teaching load per professor (total credits taught)
+-- Expected columns: professor_name, total_credits
+SELECT CONCAT(p.last_name,' ',p.first_name) AS professor_name,
+       COALESCE(SUM(c.credits),0) AS total_credits
+FROM professors p
+LEFT JOIN courses c ON p.professor_id = c.professor_id
+GROUP BY p.professor_id
+ORDER BY total_credits DESC;
+
+-- Q30. Identify overloaded courses (enrollments > 80% of max capacity)
+-- Expected columns: course_name, current_enrollments, max_capacity, percentage_full
+SELECT c.course_name,
+       COUNT(e.enrollment_id) AS current_enrollments,
+       c.max_capacity,
+       ROUND(100.0 * COUNT(e.enrollment_id) / NULLIF(c.max_capacity,0),2) AS percentage_full
+FROM courses c
+LEFT JOIN enrollments e ON c.course_id = e.course_id
+    AND e.status <> 'Dropped'
+GROUP BY c.course_id
+HAVING percentage_full > 80
+ORDER BY percentage_full DESC;
+