diff --git a/submissions/SS/talahoubri_youcef/tp1_solution.sql b/submissions/SS/talahoubri_youcef/tp1_solution.sql
new file mode 100644
index 0000000..f00aa75
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+++ b/submissions/SS/talahoubri_youcef/tp1_solution.sql
@@ -0,0 +1,501 @@
+-- Create 
+CREATE DATABASE university_db;
+USE university_db;
+
+-- Tables
+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
+);
+
+
+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),
+    FOREIGN KEY (department_id) REFERENCES departments(department_id)
+    ON DELETE SET NULL
+    ON UPDATE CASCADE
+);
+
+
+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) CHECK(level IN('L1','L2','L3','M1','M2')),
+    enrollment_date DATE,
+    FOREIGN KEY(department_id) REFERENCES departments(department_id)
+    ON DELETE SET NULL
+    ON UPDATE CASCADE
+);
+
+
+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 CHECK(credits>0),
+    semester INT CHECK(semester BETWEEN 1 AND 2),
+    department_id INT,
+    professor_id INT,
+    max_capacity INT DEFAULT 30,
+    FOREIGN KEY(department_id) REFERENCES departments(department_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    FOREIGN KEY (professor_id) REFERENCES professors(professor_id)
+        ON DELETE SET NULL
+        ON UPDATE CASCADE
+);
+
+
+CREATE TABLE enrollments (
+    enrollment_id INT PRIMARY KEY AUTO_INCREMENT,
+    student_id INT NOT NULL,
+    course_id INT NOT NULL,
+    enrollment_date DATE,
+    academic_year VARCHAR(9) NOT NULL,
+    status VARCHAR(20) DEFAULT 'in progress' 
+        CHECK(status IN('in progress','passed','failed','dropped')),
+    FOREIGN KEY(student_id) REFERENCES students(student_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    FOREIGN KEY (course_id) REFERENCES courses(course_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE,
+    UNIQUE(student_id,course_id,academic_year)
+);
+
+CREATE TABLE grades (
+    grade_id INT PRIMARY KEY AUTO_INCREMENT,
+    enrollment_id INT NOT NULL,
+    evaluation_type VARCHAR(30) 
+        CHECK(evaluation_type IN('assignment','lab','exam','project')),
+    grade DECIMAL(5,2) CHECK(grade BETWEEN 0 AND 20),
+    coefficient DECIMAL(3,2) DEFAULT 1.00,
+    evaluation_date DATE,
+    comments TEXT,
+    FOREIGN KEY(enrollment_id) REFERENCES enrollments(enrollment_id)
+        ON DELETE CASCADE
+        ON UPDATE CASCADE
+);
+
+-- 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);
+
+
+-- Insert Departments
+INSERT INTO departments (department_name,building,budget,department_head,creation_date) VALUES
+('Computer Science','A',500000,'dr benadji','2010-09-01'),
+('Mathematics','B',350000,'dr melboucy','2008-09-01'),
+('Physics','C',400000,'dr boumbbar','2009-09-01'),
+('Civil Engineering','D',600000,'dr Benbadi','2011-09-01');
+
+-- Insert Professors
+INSERT INTO professors (last_name,first_name,email,phone,department_id,hire_date,salary,specialization) VALUES
+('Berkane','Amine','a.berkane@univ-alg.dz','0554-123-456',1,'2015-09-01',68500,'AI'),
+('Saadi','Leila','l.saadi@univ-alg.dz',NULL,1,'2016-01-15',71200,'Databases'),
+('Hamdi','Karim','k_hamdi@univ-alg.dz','0661-789-012',1,'2017-09-01',65800,'Web Dev'),
+('Boukhari','Nassim','n.boukhari@univ-alg.dz','0770-234-567',2,'2014-09-01',69300,'Algebra'),
+('Ferhat','Yasmine','y.ferhat@univ-alg.dz','0555-345-678',3,'2015-09-01',70100,'Physics'),
+('Meziani','Rachid','rachid.meziani@univ-alg.dz','0662-456-789',4,'2016-09-01',72400,'Structures');
+
+-- Insert Students
+INSERT INTO students (student_number,last_name,first_name,date_of_birth,email,phone,address,department_id,level,enrollment_date) VALUES
+('221034567','Benali','Imane','2003-05-15','i.benali@etu.univ-alg.dz','0555-112-233','Cite 500 logts, Alger',1,'L3','2022-09-01'),
+('231045678','Kaci','Mehdi','2004-03-22','m.kaci@etu.univ-alg.dz',NULL,'Hai essalam, Oran',1,'L2','2023-09-01'),
+('211023456','Amrani','Yasmine','2002-11-08','y.amrani@etu.univ-alg.dz','0770-998-877','Bab ezzouar, Alger',1,'M1','2021-09-01'),
+('221056789','Brahimi','Sofiane','2003-07-30','s_brahimi@etu.univ-alg.dz','0661-223-445','Rue didouche, Constantine',2,'L3','2022-09-01'),
+('231067890','Haddad','Nour','2004-01-14','nour.haddad@etu.univ-alg.dz','0554-334-556','Cite merdja, Annaba',2,'L2','2023-09-01'),
+('221078901','Meziane','Walid','2003-09-25','w.meziane@etu.univ-alg.dz','0662-445-667','Les platanes, Oran',3,'L3','2022-09-01'),
+('211012345','Ziani','Samira','2002-12-18','samira_z@etu.univ-alg.dz',NULL,'Boumerdes centre',3,'M1','2021-09-01'),
+('221089012','Toumi','Riad','2003-04-05','r.toumi@etu.univ-alg.dz','0555-556-778','Ouled yaich, Blida',4,'L3','2022-09-01'),
+('221201235', 'Khelladi', 'Tarek', '2003-11-17', 't.khelladi@etu.univ-alg.dz', '0554-445-667', 'Casbah, Alger', 1, 'L3', '2022-09-01'),
+('231212346', 'Benslimane', 'Nadia', '2004-09-23', 'n.benslimane@etu.univ-alg.dz', NULL, 'Alger centre', 1, 'L2', '2023-09-01');
+
+-- Insert Courses
+INSERT INTO courses (course_code,course_name,description,credits,semester,department_id,professor_id,max_capacity) VALUES
+('CS101','Intro Programming','Python basics',6,1,1,1,40),
+('CS201','Database Systems','SQL and relational DB',6,1,1,2,35),
+('CS301','Web Dev','HTML CSS JS frameworks',5,2,1,3,30),
+('MATH101','Linear Algebra','Matrices vectors',6,1,2,4,45),
+('MATH201','Calculus 2','Integrals and diff equations',6,2,2,4,40),
+('PHY101','Mechanics','Newton laws',5,1,3,5,35),
+('CE201','Structural Analysis','Beams frames',6,1,4,6,28),
+('CS401', 'Advanced AI', 'Networks', 6, 2, 1, 1, 25),
+('MATH301', 'Abstract Algebra', 'Groups, rings, and fields', 5, 2, 2, 4, 30);
+
+-- Insert Enrollments
+INSERT INTO enrollments (student_id,course_id,enrollment_date,academic_year,status) VALUES
+(1,2,'2024-09-10','2024-2025','In Progress'),
+(1,3,'2024-09-15','2024-2025','In Progress'),
+(2,1,'2024-09-08','2024-2025','In Progress'),
+(2,2,'2024-09-10','2024-2025','In Progress'),
+(3,2,'2024-09-10','2024-2025','In Progress'),
+(3,3,'2024-09-12','2024-2025','In Progress'),
+(4,4,'2024-09-11','2024-2025','In Progress'),
+(4,5,'2024-09-09','2024-2025','In Progress'),
+(5,4,'2024-09-10','2024-2025','In Progress'),
+(1,1,'2023-09-05','2023-2024','Passed'),
+(2,1,'2023-09-06','2023-2024','Passed'),
+(3,1,'2023-09-05','2023-2024','Passed'),
+(6,6,'2023-09-07','2023-2024','Passed'),
+(7,6,'2023-09-05','2023-2024','Failed'),
+(8,7,'2023-09-08','2023-2024','Passed');
+
+-- Insert Grades
+INSERT INTO grades (enrollment_id,evaluation_type,grade,coefficient,evaluation_date,comments) VALUES
+(10,'Assignment',15.5,0.2,'2023-10-15','bon travail'),
+(10,'Exam',16,0.8,'2023-12-20','tres bien'),
+(11,'Assignment',14,0.2,'2023-10-18','peut mieux faire'),
+(11,'Exam',15.5,0.8,'2023-12-20','bien'),
+(12,'Lab',17,0.3,'2023-11-10','excellent'),
+(12,'Exam',18,0.7,'2023-12-22','parfait'),
+(13,'Assignment',16.5,0.4,'2023-10-20','tres bon'),
+(13,'Exam',17,0.6,'2023-12-18','excellent'),
+(14,'Exam',9.5,1.0,'2023-12-18','insuffisant'),
+(15,'Project',15,0.5,'2023-11-25','correct'),
+(15,'Exam',16,0.5,'2023-12-22','bien'),
+(1,'Assignment',14.5,0.3,'2024-10-15','bon debut');
+
+
+-- ============================================
+-- TP1: 30 SQL Queries to Solve
+-- University Management System
+-- ============================================
+-- INSTRUCTIONS: Write your SQL query below each question
+-- Test your queries before submitting!
+-- ============================================
+
+-- ========== PART 1: BASIC QUERIES (Q1-Q5) ==========
+
+-- 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;
+
+
+-- 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,CONCAT(p.first_name,' ',p.last_name) AS professor_name
+FROM courses c
+LEFT JOIN professors p ON c.professor_id =p.professor_id;
+
+
+-- Q7. List all enrollments with student name and course name
+-- Expected columns: student_name, course_name, enrollment_date, status
+SELECT CONCAT(s.first_name,' ',s.last_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;
+
+
+-- Q8. Display students with their department name
+-- Expected columns: student_name, department_name, level
+SELECT CONCAT(s.first_name,' ',s.last_name) AS student_name, d.department_name,s.level
+FROM students s
+LEFT JOIN departments d ON s.department_id = d.department_id;
+
+
+-- Q9. List grades with student name, course name, and grade obtained
+-- Expected columns: student_name, course_name, evaluation_type, grade
+SELECT CONCAT(s.first_name,' ',s.last_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 s ON e.student_id=s.student_id
+JOIN courses c ON e.course_id=c.course_id;
+
+
+-- Q10. Display professors with the number of courses they teach
+-- Expected columns: professor_name, number_of_courses
+SELECT CONCAT(p.first_name,' ',p.last_name) AS professor_name,COUNT(c.course_id) AS number_of_courses
+FROM professors p
+JOIN courses c ON p.professor_id=c.professor_id
+GROUP BY p.professor_id ,p.first_name ,p.last_name;
+
+
+-- ========== PART 3: AGGREGATE FUNCTIONS (Q11-Q15) ==========
+
+-- Q11. Calculate the overall average grade for each student
+-- Expected columns: student_name, average_grade
+SELECT CONCAT(s.first_name,' ',s.last_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,s.first_name,s.last_name;
+
+
+-- 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,d.department_name;
+
+
+-- Q13. Calculate the total budget of all departments
+-- Expected result: One row with total_budget
+SELECT SUM(budget) 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,d.department_name ;
+
+
+-- Q15. Calculate the average salary of professors per department
+-- Expected columns: department_name, average_salary
+SELECT d.department_name,AVG(p.salary) AS average_salary
+FROM departments d
+LEFT JOIN professors p ON d.department_id=p.department_id
+GROUP BY d.department_id,d.department_name;
+
+
+-- ========== PART 4: ADVANCED QUERIES (Q16-Q20) ==========
+
+-- Q16. Find the top 3 students with the best averages
+-- Expected columns: student_name, average_grade
+-- Order by average_grade DESC, limit 3
+SELECT CONCAT(s.first_name,' ',s.last_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,s.first_name,s.last_name
+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.first_name, ' ',s.last_name) AS student_name, COUNT(e.enrollment_id) AS nbr_passed
+FROM students s
+JOIN enrollments e ON s.student_id = e.student_id AND e.status = 'Passed'
+WHERE NOT EXISTS (
+    SELECT 1
+    FROM enrollments e2
+    WHERE e2.student_id = s.student_id AND e2.status <> 'Passed'
+)
+GROUP BY s.student_id, s.first_name, s.last_name;
+
+
+
+-- Q19. Find professors who teach more than 2 courses
+-- Expected columns: professor_name, courses_taught
+SELECT CONCAT(p.first_name,' ',p.last_name) AS professor_name,COUNT(c.course_id) AS p_courses
+FROM professors p
+JOIN courses c ON p.professor_id=c.professor_id
+GROUP BY p.professor_id,p.first_name,p.last_name
+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.first_name,' ',s.last_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 ,s.first_name ,s.last_name
+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 CONCAT(s.first_name,' ',s.last_name) AS student_name,AVG(g.grade) AS student_avg,
+       (SELECT AVG(g2.grade)
+        FROM students s2
+        JOIN enrollments e2 ON s2.student_id=e2.student_id
+        JOIN grades g2 ON e2.enrollment_id=g2.enrollment_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 e.enrollment_id=g.enrollment_id
+GROUP BY s.student_id,s.first_name ,s.last_name ,s.department_id
+HAVING AVG(g.grade)>(
+    SELECT AVG(g2.grade)
+    FROM students s2
+    JOIN enrollments e2 ON s2.student_id=e2.student_id
+    JOIN grades g2 ON e2.enrollment_id=g2.enrollment_id
+    WHERE s2.department_id=s.department_id
+);
+
+
+-- Q22. List courses with more enrollments than the average number of enrollments
+-- Expected columns: course_name, enrollment_count
+SELECT c.course_name,COUNT(e.enrollment_id) AS enrollment_count
+FROM courses c
+JOIN enrollments e ON c.course_id=e.course_id
+GROUP BY c.course_id,c.course_name
+HAVING COUNT(e.enrollment_id)>(
+    SELECT AVG(enrollment_count)
+    FROM (
+        SELECT COUNT(enrollment_id) AS enrollment_count
+        FROM enrollments
+        GROUP BY course_id
+    ) AS avg_enrollments
+);
+
+
+-- Q23. Display professors from the department with the highest budget
+-- Expected columns: professor_name, department_name, budget
+SELECT CONCAT(p.first_name,' ',p.last_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.first_name,' ',s.last_name) AS student_name,s.email
+FROM students s
+WHERE s.student_id NOT IN(
+    SELECT DISTINCT e.student_id
+    FROM enrollments e
+    JOIN grades g ON e.enrollment_id=g.enrollment_id
+);
+
+
+-- Q25. List departments with more students than the average
+-- Expected columns: department_name, student_count
+SELECT d.department_name,COUNT(s.student_id) AS student_count
+FROM departments d
+JOIN students s ON d.department_id=s.department_id
+GROUP BY d.department_id ,d.department_name
+HAVING COUNT(s.student_id)>(
+    SELECT AVG(student_count)
+    FROM (
+        SELECT COUNT(student_id) AS student_count
+        FROM students
+        GROUP BY department_id
+    ) AS avg_students
+);
+
+
+-- ========== 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,
+      (SUM(CASE WHEN g.grade>=10 THEN 1 ELSE 0 END)/COUNT(g.grade_id))*100 AS pass_rate_percentage
+FROM courses c
+JOIN enrollments e ON c.course_id = e.course_id
+JOIN grades g ON e.enrollment_id =g.enrollment_id
+GROUP BY c.course_id, c.course_name ;
+
+
+-- Q27. Display student ranking by descending average
+-- Expected columns: rank, student_name, average_grade
+SELECT
+    1 + (
+        SELECT COUNT(*)
+        FROM (
+            SELECT AVG(g2.grade) AS avg_grade
+            FROM students s2
+            JOIN enrollments e2 ON s2.student_id= e2.student_id
+            JOIN grades g2 ON e2.enrollment_id= g2.enrollment_id
+            GROUP BY s2.student_id) AS all_avgs
+        WHERE all_avgs.avg_grade>t.average_grade
+    ) AS `rank`,  t.student_name,   t.average_grade
+FROM (
+    SELECT s.student_id, CONCAT(s.first_name, ' ', s.last_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, s.first_name, s.last_name
+) AS t
+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, g.grade * g.coefficient 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.first_name,' ',p.last_name) AS professor_name, SUM(c.credits) AS total_credits
+FROM professors p
+LEFT JOIN courses c ON p.professor_id=c.professor_id
+GROUP BY p.professor_id,p.first_name,p.last_name;
+
+
+-- 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,(COUNT(e.enrollment_id)/c.max_capacity)*100 AS percentage_full
+FROM courses c
+JOIN enrollments e ON c.course_id=e.course_id
+GROUP BY c.course_id, c.course_name, c.max_capacity
+HAVING (COUNT(e.enrollment_id)/c.max_capacity) *100 > 80
+ORDER BY percentage_full DESC;