php如何获取mysql表的所有数据

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

try {
    // 创建PDO连接
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置PDO错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 查询语句
    $sql = "SELECT * FROM table_name";
    // 执行查询
    $stmt = $conn->query($sql);

    // 遍历结果集并输出
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        echo "id: " . $row["id"] . " - Name: " . $row["name"] . "<br>";
    }
} catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}

// 关闭连接
$conn = null;
?>