php语言之mysql操作答案

好的，我来回答你的问题。PHP语言可以通过MySQL扩展库来连接和操作MySQL数据库。以下是连接和查询MySQL数据库的示例代码：

连接MySQL数据库：

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

// 创建连接
$conn = new mysqli($servername, $username, $password);

// 检测连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

查询MySQL数据库：

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

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}

// 查询数据
$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();
?>

以上是基本的连接和查询MySQL数据库的代码示例，希望能对你有所帮助。