php访问mysql数据库方法

<?php
// 连接数据库
$conn = new mysqli("localhost", "username", "password", "database");

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接数据库失败: " . $conn->connect_error);
}

// 执行查询
$sql = "SELECT * FROM table";
$result = $conn->query($sql);

// 处理查询结果
if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        echo "字段1: " . $row["column1"]. " - 字段2: " . $row["column2"]. "<br>";
    }
} else {
    echo "没有数据";
}

// 关闭数据库连接
$conn->close();
?>

<?php
// 连接数据库
try {
    $conn = new PDO("mysql:host=localhost;dbname=database", "username", "password");
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "连接数据库成功";
} catch (PDOException $e) {
    die("连接数据库失败: " . $e->getMessage());
}

// 执行查询
$sql = "SELECT * FROM table";
$result = $conn->query($sql);

// 处理查询结果
if ($result->rowCount() > 0) {
    foreach ($result as $row) {
        echo "字段1: " . $row["column1"]. " - 字段2: " . $row["column2"]. "<br>";
    }
} else {
    echo "没有数据";
}

// 关闭数据库连接
$conn = null;
?>