php mysql留言板点赞

CREATE TABLE posts (
    id INT AUTO_INCREMENT PRIMARY KEY,
    content TEXT NOT NULL
);

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

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 点赞功能
if (isset($_POST['like'])) {
    $post_id = $_POST['post_id'];
    $user_id = $_POST['user_id'];

    // 检查是否已经点赞
    $sql = "SELECT * FROM likes WHERE post_id = $post_id AND user_id = $user_id";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        // 取消点赞
        $sql = "DELETE FROM likes WHERE post_id = $post_id AND user_id = $user_id";
    } else {
        // 点赞
        $sql = "INSERT INTO likes (post_id, user_id) VALUES ($post_id, $user_id)";
    }

    if ($conn->query($sql) === TRUE) {
        echo "操作成功";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

// 获取点赞数
$post_id = 1; // 假设我们要获取ID为1的帖子的点赞数
$sql = "SELECT COUNT(*) as like_count FROM likes WHERE post_id = $post_id";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    $row = $result->fetch_assoc();
    echo "点赞数: " . $row["like_count"];
} else {
    echo "0";
}

$conn->close();
?>