密码加密登录问题

Question

Im having problem looking up and verifying a user's encrypted password in my sql database. The registration process is fine, it creates their row with their md5 ecrypted password but then when trying to log in, it won't recognize their password. Heres what im using:

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
mysql_select_db("$db_name")or die("cannot select DB");

// username and password sent from form 
$myusername = $_POST['myusername']; 
$mypassword = $_POST['mypassword']; 

// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='md5($mypassword)'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row
if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"
session_start();
$_SESSION['login'] = "$myusername";

Answer 1

Try

mysql_connect($host, $username, $password)or die("cannot connect"); 
mysql_select_db($db_name)or die("cannot select DB");

// username and password sent from form 
$myusername = $_POST['myusername']; 
$mypassword = $_POST['mypassword']; 

// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);

$sql="SELECT * FROM '".$tbl_name.". WHERE username='".$myusername."' and password='".md5($mypassword)."'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row
if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"
session_start();
$_SESSION['login'] = $myusername;