PHP计数值在数据库中并在表格中显示

<?php
// 步骤1：创建数据库表格
// 假设数据库名为"mydatabase"，表格名为"mytable"，包含两列：id和count_value
// id列为自增主键，count_value列用于存储计数值
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "mydatabase";

$conn = new mysqli($servername, $username, $password, $dbname);

// 步骤2：连接数据库
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 步骤3：查询数据库
$sql = "SELECT count_value FROM mytable";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        $count_value = $row["count_value"];
        echo "计数值: " . $count_value;
    }
} else {
    echo "0 结果";
}

// 步骤4：更新计数值
// 假设要将计数值加1
$sql = "UPDATE mytable SET count_value = count_value + 1";
$conn->query($sql);

// 步骤5：显示计数值
echo "<table>";
echo "<tr><th>计数值</th></tr>";
echo "<tr><td>" . $count_value . "</td></tr>";
echo "</table>";

$conn->close();
?>