PHP连接MySQL数据库步骤 PHP源码操作MySQL详细教程

<?php
$servername = "localhost"; // 数据库服务器地址，通常是localhost
$username = "your_username"; // 你的MySQL用户名
$password = "your_password"; // 你的MySQL密码
$database = "your_database"; // 你要连接的数据库名

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

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

// 执行SQL查询
$sql = "SELECT id, name FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
  // 输出每行数据
  while($row = $result->fetch_assoc()) {
    echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
  }
} else {
  echo "0 结果";
}

// 关闭连接
$conn->close();
?>

<?php
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$database = "your_database";

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

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

// 准备SQL语句
$sql = "SELECT id, name FROM users WHERE username = ?";

// 创建预处理语句
$stmt = $conn->prepare($sql);

// 绑定参数
$username = $_POST['username']; // 假设用户名是通过POST方法传递过来的
$stmt->bind_param("s", $username); // "s"表示参数是字符串类型

// 执行查询
$stmt->execute();

// 获取结果
$result = $stmt->get_result();

if ($result->num_rows > 0) {
  // 输出每行数据
  while($row = $result->fetch_assoc()) {
    echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
  }
} else {
  echo "0 结果";
}

// 关闭语句和连接
$stmt->close();
$conn->close();
?>

<?php
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$database = "your_database";

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

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

  // 执行SQL查询
  $sql = "SELECT id, name FROM users";
  $result = $conn->query($sql);

  if ($result === false) {
    throw new Exception("查询失败: " . $conn->error);
  }

  if ($result->num_rows > 0) {
    // 输出每行数据
    while($row = $result->fetch_assoc()) {
      echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
  } else {
    echo "0 结果";
  }

  // 关闭连接
  $conn->close();

} catch (Exception $e) {
  echo "发生错误: " . $e->getMessage();
}
?>