mysql php错误处理

try {
    $conn = new mysqli("localhost", "username", "password", "database");
    if ($conn->connect_error) {
        die("连接失败: " . $conn->connect_error);
    }
} catch (Exception $e) {
    echo "数据库连接异常: " . $e->getMessage();
}

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

if ($result === false) {
    echo "查询失败: " . $conn->error;
} else {
    // 处理查询结果
}

$sql = "INSERT INTO MyGuests (firstname, lastname, email) VALUES ('John', 'Doe', 'john@example.com')";
if ($conn->query($sql) === true) {
    echo "新记录插入成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$sql = "UPDATE MyGuests SET email = 'john.doe@example.com' WHERE id = 1";
if ($conn->query($sql) === true) {
    echo "记录更新成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}