php编程怎么和mysql连接

php连接mysql的方法：

MySQLi - 面向对象

<?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";
?>

MySQLi - 面向过程

<?php
$servername = "localhost";
$username = "username";
$password = "password";
 
// 创建连接
$conn = mysqli_connect($servername, $username, $password);
 
// 检测连接
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "连接成功";
?>

关闭连接

连接在脚本执行完后会自动关闭。你也可以使用以下代码来关闭连接：

(MySQLi - 面向对象

$conn->close();

MySQLi - 面向过程

mysqli_close($conn);