diff --git a/submissions/SS/naceri_rim_serine/tp1_solutions.sql b/submissions/SS/naceri_rim_serine/tp1_solutions.sql
new file mode 100644
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+++ b/submissions/SS/naceri_rim_serine/tp1_solutions.sql
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+-- PART 1: the set up
+-- 1. database creation
+DROP DATABASE IF EXISTS university_db;
+CREATE DATABASE university_db;
+USE university_db;
+
+-- 2. TABLE CREATION
+
+-- 2.1 departments table
+CREATE TABLE departments (
+    department_id INT PRIMARY KEY AUTO_INCREMENT,
+    department_name VARCHAR(100) NOT NULL,
+    building VARCHAR(50),
+    budget DECIMAL(12, 2),
+    department_head VARCHAR(100),
+    creation_date DATE
+);
+
+-- 2.2 professors table
+CREATE TABLE professors (
+    professor_id INT PRIMARY KEY AUTO_INCREMENT,
+    last_name VARCHAR(50) NOT NULL,
+    first_name VARCHAR(50) NOT NULL,
+    email VARCHAR(100) UNIQUE NOT NULL,
+    phone VARCHAR(20),
+    department_id INT,
+    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
+);
+
+-- 2.3 students table
+CREATE TABLE students (
+    student_id INT PRIMARY KEY AUTO_INCREMENT,
+    student_number VARCHAR(20) UNIQUE NOT NULL,
+    last_name VARCHAR(50) NOT NULL,
+    first_name VARCHAR(50) NOT NULL,
+    date_of_birth DATE,
+    email VARCHAR(100) UNIQUE NOT NULL,
+    phone VARCHAR(20),
+    address TEXT,
+    department_id INT,
+    level VARCHAR(20),
+    enrollment_date DATE DEFAULT (CURRENT_DATE),
+    CONSTRAINT fk_student_dept FOREIGN KEY (department_id) 
+        REFERENCES departments(department_id) 
+        ON DELETE SET NULL 
+        ON UPDATE CASCADE,
+    CONSTRAINT chk_level CHECK (level IN ('L1', 'L2', 'L3', 'M1', 'M2'))
+);
+
+-- 2.4 courses table
+CREATE TABLE courses (
+    course_id INT PRIMARY KEY AUTO_INCREMENT,
+    course_code VARCHAR(10) UNIQUE NOT NULL,
+    course_name VARCHAR(150) NOT NULL,
+    description TEXT,
+    credits INT NOT NULL,
+    semester INT,
+    department_id INT,
+    professor_id INT,
+    max_capacity INT DEFAULT 30,
+    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,
+    CONSTRAINT chk_credits CHECK (credits > 0),
+    CONSTRAINT chk_semester CHECK (semester BETWEEN 1 AND 2)
+);
+
+-- 2.5 enrollments table
+CREATE TABLE enrollments (
+    enrollment_id INT PRIMARY KEY AUTO_INCREMENT,
+    student_id INT NOT NULL,
+    course_id INT NOT NULL,
+    enrollment_date DATE DEFAULT (CURRENT_DATE),
+    academic_year VARCHAR(9) NOT NULL,
+    status VARCHAR(20) DEFAULT 'In Progress',
+    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 uq_enrollment UNIQUE (student_id, course_id, academic_year),
+    CONSTRAINT chk_status CHECK (status IN ('In Progress', 'Passed', 'Failed', 'Dropped'))
+);
+
+-- 2.6 grades table
+CREATE TABLE grades (
+    grade_id INT PRIMARY KEY AUTO_INCREMENT,
+    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 fk_grade_enrollment FOREIGN KEY (enrollment_id) 
+        REFERENCES enrollments(enrollment_id) 
+        ON DELETE CASCADE 
+        ON UPDATE CASCADE,
+    CONSTRAINT chk_eval_type CHECK (evaluation_type IN ('Assignment', 'Lab', 'Exam', 'Project')),
+    CONSTRAINT chk_grade CHECK (grade BETWEEN 0 AND 20)
+);
+
+-- 3. indexes creation
+
+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);
+
+-- 4. data insertion
+
+-- departments 
+INSERT INTO departments (department_name, building, budget, department_head, creation_date) VALUES 
+('Computer Science', 'Building A', 500000.00, 'Dr. Alan Turing', '2000-01-15'),
+('Mathematics', 'Building B', 350000.00, 'Dr. Ada Lovelace', '1998-05-20'),
+('Physics', 'Building C', 400000.00, 'Dr. Albert Einstein', '2005-09-01'),
+('Civil Engineering', 'Building D', 600000.00, 'Dr. Isambard Brunel', '2010-03-12');
+
+-- professors 
+INSERT INTO professors (last_name, first_name, email, phone, department_id, hire_date, salary, specialization) VALUES 
+('Smith', 'John', 'j.smith@uni.edu', '555-0101', 1, '2015-08-20', 75000.00, 'Artificial Intelligence'),
+('Doe', 'Jane', 'j.doe@uni.edu', '555-0102', 1, '2018-01-15', 72000.00, 'Cybersecurity'),
+('Brown', 'Robert', 'r.brown@uni.edu', '555-0103', 1, '2012-11-05', 80000.00, 'Software Engineering'),
+('Wilson', 'Emily', 'e.wilson@uni.edu', '555-0201', 2, '2016-09-01', 68000.00, 'Linear Algebra'),
+('Taylor', 'David', 'd.taylor@uni.edu', '555-0301', 3, '2019-02-14', 71000.00, 'Quantum Physics'),
+('Anderson', 'Sarah', 's.anderson@uni.edu', '555-0401', 4, '2014-06-23', 76000.00, 'Structural Engineering');
+
+-- students 
+INSERT INTO students (student_number, last_name, first_name, date_of_birth, email, phone, department_id, level) VALUES 
+('S2023001', 'Martin', 'Alice', '2002-04-15', 'alice.m@student.uni.edu', '555-1001', 1, 'L2'),
+('S2023002', 'Garcia', 'Carlos', '2001-08-22', 'carlos.g@student.uni.edu', '555-1002', 1, 'L3'),
+('S2023003', 'Lee', 'Min-Ji', '2003-12-05', 'minji.l@student.uni.edu', '555-1003', 2, 'L2'),
+('S2023004', 'Dubois', 'Thomas', '2000-02-28', 'thomas.d@student.uni.edu', '555-1004', 3, 'M1'),
+('S2023005', 'Khan', 'Fatima', '2001-11-12', 'fatima.k@student.uni.edu', '555-1005', 4, 'L3'),
+('S2023006', 'Muller', 'Hans', '1999-07-30', 'hans.m@student.uni.edu', '555-1006', 1, 'M2'),
+('S2023007', 'Rossi', 'Marco', '2002-09-19', 'marco.r@student.uni.edu', '555-1007', 2, 'L2'),
+('S2023008', 'Tanaka', 'Ken', '2001-03-14', 'ken.t@student.uni.edu', '555-1008', 3, 'M1');
+
+-- courses 
+INSERT INTO courses (course_code, course_name, description, credits, semester, department_id, professor_id) VALUES 
+('CS101', 'Intro to Programming', 'Python basics', 6, 1, 1, 1),
+('CS202', 'Data Structures', 'Advanced algorithms', 6, 2, 1, 3),
+('CS305', 'Network Security', 'Security protocols', 5, 1, 1, 2),
+('MATH101', 'Calculus I', 'Derivatives and integrals', 6, 1, 2, 4),
+('PHYS201', 'Mechanics', 'Newtonian physics', 5, 2, 3, 5),
+('CIV301', 'Materials Science', 'Construction materials', 5, 1, 4, 6),
+('MATH201', 'Linear Algebra', 'Matrices and vectors', 5, 2, 2, 4);
+
+-- enrollments 
+INSERT INTO enrollments (student_id, course_id, academic_year, status) VALUES 
+(1, 1, '2024-2025', 'In Progress'), 
+(1, 4, '2024-2025', 'In Progress'), 
+(2, 2, '2024-2025', 'In Progress'), 
+(2, 3, '2024-2025', 'In Progress'), 
+(6, 3, '2023-2024', 'Passed'),      
+(3, 4, '2024-2025', 'In Progress'), 
+(3, 7, '2024-2025', 'In Progress'), 
+(4, 5, '2024-2025', 'In Progress'), 
+(5, 6, '2024-2025', 'In Progress'), 
+(7, 4, '2024-2025', 'Failed'),      
+(8, 5, '2023-2024', 'Passed'),      
+(6, 2, '2024-2025', 'In Progress'), 
+(2, 7, '2024-2025', 'Dropped'),     
+(1, 7, '2024-2025', 'In Progress'), 
+(5, 1, '2023-2024', 'Passed');      
+
+-- grades 
+INSERT INTO grades (enrollment_id, evaluation_type, grade, coefficient, evaluation_date, comments) VALUES 
+(5, 'Exam', 16.50, 1.00, '2024-01-15', 'Excellent work'),
+(5, 'Project', 18.00, 0.50, '2023-12-20', 'Good implementation'),
+(11, 'Exam', 14.00, 1.00, '2024-01-10', 'Good'),
+(15, 'Exam', 12.50, 1.00, '2024-01-12', 'Satisfactory'),
+(1, 'Assignment', 15.00, 0.20, '2024-10-10', 'First assignment'),
+(2, 'Exam', 11.00, 1.00, '2024-11-05', 'Needs improvement'),
+(3, 'Lab', 17.00, 0.40, '2024-10-25', 'Perfect code'),
+(10, 'Exam', 08.50, 1.00, '2024-11-05', 'Failed exam'),
+(6, 'Assignment', 13.50, 0.20, '2024-10-15', 'Average'),
+(4, 'Project', 19.00, 0.50, '2024-12-01', 'Outstanding'),
+(7, 'Exam', 10.00, 1.00, '2024-11-20', 'Just passed'),
+(12, 'Lab', 15.50, 0.40, '2024-10-20', 'Good participation');
+
+-- PART 2: the queries
+
+-- Q1: 
+select s.last_name, s.first_name, s.email, s.level 
+from students s;
+
+-- Q2:
+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:
+select c.course_code, c.course_name, c.credits 
+from courses c 
+where credits > 5;
+
+-- Q4:
+select s.student_number, s.last_name, s.first_name, s.email 
+from students s
+where s.level ="L3";
+
+-- Q5:
+select c.course_code, c.course_name, c.credits, c.semester 
+from courses c
+where c.semester = "1";
+
+-- Q6:
+select c.course_code, c.course_name, p.last_name, p.first_name 
+from courses c 
+join professors p 
+on p.professor_id = c.professor_id;
+
+-- Q7:
+select s.first_name, s.last_name, c.course_name, e.enrollment_date, e.status 
+from students s 
+join enrollments e 
+on e.student_id = s.student_id 
+join courses c 
+on c.course_id = e.course_id;
+
+-- Q8:
+select s.last_name, s.first_name, s.level, d.department_name 
+from students s 
+join departments d 
+on s.department_id = d.department_id;
+
+-- Q9:
+select s.last_name, s.first_name, c.course_name, g.evaluation_type, g.grade 
+from enrollments e 
+join students s 
+on e.student_id = s.student_id 
+join grades g 
+on g.enrollment_id = e.enrollment_id 
+join courses c 
+on c.course_id = e.course_id;
+
+-- Q10:
+select p.first_name, p.last_name, count(c.professor_id) as number_of_courses 
+from professors p 
+join courses c 
+on c.professor_id = p.professor_id 
+group by c.professor_id;
+
+-- Q11:
+select s.last_name, s.first_name, avg(g.grade) as average_grade 
+from students s 
+join enrollments e 
+on e.student_id = s.student_id 
+join grades g 
+on g.enrollment_id = e.enrollment_id 
+group by s.student_id;
+
+-- Q12:
+select d.department_name, count(s.student_id) as student_count 
+from students s 
+left join departments d 
+on d.department_id = s.department_id 
+group by d.department_id;
+
+-- Q13:
+select sum(budget) as total_budget from departments;
+
+-- Q14:
+select d.department_name, count(c.course_id) as course_count 
+from courses c 
+left join departments d 
+on d.department_id = c.department_id 
+group by c.department_id;
+
+-- Q15:
+select d.department_name, avg(p.salary) 
+from professors p 
+join departments d 
+on d.department_id = p.department_id 
+group by p.department_id; 
+-- or 
+-- select d.department_name, avg(p.salary) 
+-- from professors p 
+-- join departments d on d.department_id = p.department_id 
+-- group by d.department_id;
+
+-- Q16:
+select s.first_name, s.last_name, avg(g.grade) as average_grade 
+from grades g 
+join enrollments e 
+on e.enrollment_id = g.enrollment_id 
+join students s 
+on s.student_id = e.student_id 
+group by s.student_id 
+order by average_grade desc limit 3;
+
+-- Q17:
+select c.course_code, c.course_name 
+from courses c 
+left join enrollments e 
+on e.course_id = c.course_id 
+where student_id is null;
+
+-- Q18:
+select s.first_name, s.last_name, count(*) as passed_courses 
+from students s 
+join enrollments e 
+on e.student_id = s.student_id group by s.student_id 
+having count(*) = sum(e.status = "Passed");
+
+-- Q19:
+select p.last_name, p.first_name, count(c.course_id) as courses_taught 
+from professors p 
+join courses c 
+on c.professor_id = p.professor_id 
+group by p.professor_id 
+having count(c.course_id);
+
+-- Q20:
+select s.first_name, s.last_name, count(c.course_id) as enrolled_courses_count 
+from students s 
+join enrollments e 
+on e.student_id = s.student_id 
+join courses c 
+on c.course_id = e.course_id 
+group by s.student_id 
+having count(c.course_id) > 2;
+
+-- Q21:
+select s.last_name, s.first_name, avg(g.grade) as student_average, (
+    select avg(g2.grade) as department_average 
+    from grades g2 
+    join enrollments e2 
+    on e2.enrollment_id = g2.enrollment_id 
+    join students s2 
+    on s2.student_id = e2.student_id 
+    where s2.department_id = s.department_id) as department_avg 
+from students s 
+join enrollments e 
+on s.student_id = e.student_id 
+join grades g 
+on g.enrollment_id = e.enrollment_id 
+group by s.student_id, s.first_name, s.last_name, s.department_id 
+having avg(g.grade) > (
+    select avg(g2.grade) as department_average 
+    from grades g2 
+    join enrollments e2 
+    on e2.enrollment_id = g2.enrollment_id 
+    join students s2 
+    on s2.student_id = e2.student_id 
+    where s2.department_id = s.department_id);
+
+-- Q22:
+select c.course_name, count(e.enrollment_id) as enrollment_count
+from courses c
+left join enrollments e 
+on e.course_id = c.course_id
+group by c.course_id, c.course_name
+having count(e.enrollment_id) > (
+    select avg(course_count)
+    from (
+        select count(e2.enrollment_id) as course_count
+        from courses c2
+        left join enrollments e2 
+        on e2.course_id = c2.course_id
+        group by c2.course_id
+    ) as sub
+);
+
+-- Q23:
+select p.first_name,  p.last_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: 
+select s.first_name, s.last_name, s.email
+from students s
+left join enrollments e 
+on s.student_id = e.student_id
+left join grades g 
+on e.enrollment_id = g.enrollment_id
+where g.grade is null;
+
+-- Q25:
+select d.department_name, count(s.student_id) as student_count
+from departments d
+left join  students s 
+on s.department_id = d.department_id
+group by d.department_id, d.department_name
+having count(s.student_id) > (
+    select avg(student_count) 
+    from (
+        select count(s2.student_id) as student_count
+        from departments d2
+        left join  students s2 
+        on s2.department_id = d2.department_id
+        group by d2.department_id
+    ) as sub
+);
+
+-- Q26:
+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 * sum(case when g.grade >= 10 then 1 else 0 end)/count(g.grade_id), 2) as pass_rate_percentage
+from courses c
+join enrollments e 
+on e.course_id = c.course_id
+join grades g 
+on g.enrollment_id = e.enrollment_id
+group by c.course_id, c.course_name;
+
+-- Q27:
+select
+    rank() over (order by avg(g.grade) desc) as rank,
+    s.first_name,  s.last_name,
+    round(avg(g.grade), 2) as average_grade
+from students s
+join enrollments e 
+on e.student_id = s.student_id
+join grades g 
+on g.enrollment_id = e.enrollment_id
+group by s.student_id, s.first_name, s.last_name
+order by average_grade desc;
+
+-- Q28:
+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;
+
+-- Q29:
+select p.first_name,  p.last_name, sum(c.credits) as total_credits
+from professors p
+join courses c 
+on c.professor_id = p.professor_id
+group by p.professor_id, p.first_name, p.last_name;
+
+-- Q30:
+select 
+    c.course_name,
+    count(e.enrollment_id) as current_enrollments,
+    c.max_capacity,
+    round(100 * count(e.enrollment_id)/c.max_capacity, 2) as percentage_full
+from courses c
+left join enrollments e 
+on e.course_id = c.course_id
+group by c.course_id, c.course_name, c.max_capacity
+having percentage_full > 80;