CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) UNIQUE NOT NULL,
    email VARCHAR(100) UNIQUE NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE posts (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT,
    title VARCHAR(255) NOT NULL,
    content TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES users(id)
);

CREATE TABLE comments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    post_id INT,
    user_id INT,
    content TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (post_id) REFERENCES posts(id),
    FOREIGN KEY (user_id) REFERENCES users(id)
);

INSERT INTO users (username, email) VALUES
('john_doe', 'john@example.com'),
('jane_smith', 'jane@example.com');

INSERT INTO posts (user_id, title, content) VALUES
(1, 'First Post', 'This is the content of the first post.'),
(2, 'Hello World', 'Hello everyone! This is my first post.');

INSERT INTO comments (post_id, user_id, content) VALUES
(1, 2, 'Great post!'),
(2, 1, 'Welcome to the community!');