mysql抛出异常

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

// 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);
}

try {
    // 尝试执行 SQL 语句
    $sql = "SELECT * FROM non_existent_table";
    $result = $conn->query($sql);

    if ($result === false) {
        throw new Exception("SQL 语句执行失败: " . $conn->error);
    }

    // 处理结果集
    while ($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"] . " - Name: " . $row["name"] . "<br>";
    }
} catch (Exception $e) {
    // 捕获并处理异常
    echo "发生异常: " . $e->getMessage();
} finally {
    // 关闭连接
    $conn->close();
}
?>