php打印mysql错误信息

<?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);
}

// 设置错误报告级别
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

// 执行查询
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);

if ($result) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
} else {
    // 打印错误信息
    echo "查询失败: " . $conn->error;
}

// 关闭连接
$conn->close();
?>