点赞和总点赞数的数据库设计

以下是一个简单的数据库设计，包含点赞和总点赞数的表结构和代码示例。

1. 创建点赞表（likes）：

CREATE TABLE likes (
  id INT PRIMARY KEY AUTO_INCREMENT,
  post_id INT NOT NULL,
  user_id INT NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (post_id) REFERENCES posts(id),
  FOREIGN KEY (user_id) REFERENCES users(id)
);

2. 创建帖子表（posts）：

CREATE TABLE posts (
  id INT PRIMARY KEY AUTO_INCREMENT,
  title VARCHAR(255) NOT NULL,
  content TEXT NOT NULL,
  total_likes INT DEFAULT 0
);

3. 创建用户表（users）：

CREATE TABLE users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  username VARCHAR(255) NOT NULL,
  email VARCHAR(255) NOT NULL
);

4. 插入示例数据：

INSERT INTO posts (title, content) VALUES ('Post 1', 'Content 1');
INSERT INTO posts (title, content) VALUES ('Post 2', 'Content 2');
INSERT INTO posts (title, content) VALUES ('Post 3', 'Content 3');

INSERT INTO users (username, email) VALUES ('User 1', 'user1@example.com');
INSERT INTO users (username, email) VALUES ('User 2', 'user2@example.com');
INSERT INTO users (username, email) VALUES ('User 3', 'user3@example.com');

5. 插入点赞数据：

INSERT INTO likes (post_id, user_id) VALUES (1, 1); -- 用户1点赞了帖子1
INSERT INTO likes (post_id, user_id) VALUES (1, 2); -- 用户2点赞了帖子1
INSERT INTO likes (post_id, user_id) VALUES (2, 1); -- 用户1点赞了帖子2
INSERT INTO likes (post_id, user_id) VALUES (3, 3); -- 用户3点赞了帖子3

6. 查询帖子总点赞数：

SELECT posts.id, posts.title, COUNT(likes.id) AS total_likes
FROM posts
LEFT JOIN likes ON posts.id = likes.post_id
GROUP BY posts.id, posts.title;

这将返回一个结果集，包含帖子的ID、标题和总点赞数。

希望以上信息能对您有所帮助！