CREATE TABLE Instructor ( 
ID INT PRIMARY KEY, 
Name VARCHAR(100), 
Department VARCHAR(100)
);


CREATE TABLE Course (
    ID INT PRIMARY KEY,
    Title VARCHAR(150),
    Credits INT,
    Instructor_ID INT,
    FOREIGN KEY (Instructor_ID) REFERENCES Instructor(ID)
);

INSERT INTO Instructor (ID, Name, Department)
VALUES 
(1, 'Dr. Alice Morgan', 'Computer Science'),
(2, 'Dr. Ben Carter', 'Mathematics'),
(3, 'Dr. Clara Zhang', 'Physics');

INSERT INTO Course (ID, Title, Credits, Instructor_ID)
VALUES 
(10, 'Data Structures', 4, 1),
(11, 'Calculus I', 3, 2),
(12, 'Quantum Mechanics', 5, 3),
(13, 'Discrete Math', 3, NULL),
(14, 'Algorithms', 4, 1);

SELECT Instructor.Name, Course.Title
FROM Instructor 
LEFT JOIN Course ON Instructor.ID = Course.Instructor_ID;

UPDATE Course 
SET ID = 2 
WHERE ID = 10; 

SELECT Title 
FROM Course 
WHERE Credits > 3 AND Instructor_ID IS NULL;


SELECT Instructor.Name, COUNT(*) AS Total_Courses 
FROM Instructor 
LEFT JOIN Course ON Instructor_ID = Course.Instructor_ID 
GROUP BY Instructor.Name 
ORDER BY Instructor.Name ASC; 

SELECT DISTINCT Title 
FROM Course;