mysql_query 连续操作

// 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);
}

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

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
} else {
    echo "0 结果";
}
$conn->close();

// 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);
}

// 准备 SQL 语句
$stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests WHERE firstname=? AND lastname=?");
$stmt->bind_param("ss", $firstname, $lastname);

// 设置参数并执行
$firstname = "John";
$lastname = "Doe";
$stmt->execute();

// 绑定结果变量
$stmt->bind_result($id, $firstname, $lastname);

// 获取结果并输出
while ($stmt->fetch()) {
    echo "id: " . $id . " - Name: " . $firstname . " " . $lastname . "<br>";
}

$stmt->close();
$conn->close();