PHP 访问mysql的学习心得之一（登录）

用PHP加mysql写的一个login

<?php

$username = $_GET['account'];
$password=$_GET['pwd'];

$user = new mysqli();
if($user)
{
$user->connect("localhost", "root", "123456", "test_db");
if (mysqli_connect_errno()) {
//printf("Connect failed: %s\n", mysqli_connect_error());
$arr = array(
'code'=>'400',
'info'=>"系统错误!",
);
echo json_encode($arr,JSON_UNESCAPED_UNICODE);
exit();
}
}
else
{
$arr = array(
'code'=>'400',
'info'=>"系统错误!",
);
echo json_encode($arr,JSON_UNESCAPED_UNICODE);
exit();
}

$user->query("set names 'utf8' ");

$query = "SELECT * FROM users where account='$username' and password='$password' limit 1";
//Use a variable to save result
$result = $user->query($query);
if($result)
{
if ($result->num_rows > 0)
{

$arr = array(
'code'=>'200',
'info'=>"登录成功!",
'data'=>$result->fetch_all()
);

echo json_encode($arr,JSON_UNESCAPED_UNICODE);

}

else
{
$arr = array(
'code'=>'400',
'info'=>"错误的用户名和密码!",
);

echo json_encode($arr,JSON_UNESCAPED_UNICODE);
}

/* free result set */
$result->close();
}
else
{
$arr = array(
'code'=>'400',
'info'=>"系统错误!",
);

echo json_encode($arr,JSON_UNESCAPED_UNICODE);
}

$user->close();

?>