php - Can someone help me find out the meaning behind these errors? -

possible duplicate:
can me figure out meaning of php error message?

here code:

$con = mysql_connect("localhost", "root", '');  if (!$con) {     die('cannot make connection'); }   mysql_select_db('yumbox_table', $con) or die('cannot make connection');  $user_name = mysql_real_escape_string($_post['user_name']); $password = mysql_real_escape_string($_post['password']); $user_type = mysql_real_escape_string($_post['user_type']);    $data = mysql_query("select * users user_name == '$user_name' , password == '$password' user_type == '$user_type'") or die(mysql_error());  $info = mysql_fetch_array($data);  $count = mysql_numrows($data);  if ($count==1) {     echo ("success!!"); } else  {     echo ("big friggin failure!!"); }    mysql_close($con); 

and these error messages generated said code:

notice: undefined index: user_name in c:\wamp\www\login.php on line 12 call stack #   time    memory  function    location 1   0.0013  371904  {main}( )   ..\login.php:0  ( ! ) notice: undefined index: password in c:\wamp\www\login.php on line 13 call stack #   time    memory  function    location 1   0.0013  371904  {main}( )   ..\login.php:0  ( ! ) notice: undefined index: user_type in c:\wamp\www\login.php on line 14 call stack #   time    memory  function    location 1   0.0013  371904  {main}( )   ..\login.php:0  have error in sql syntax; check manual corresponds mysql server version right syntax use near '== '' , password == '' user_type == ''' @ line 1 

• some of variables not set. empty. therefore undefined index messages
• your query wring also. comparison operator strings =, not ==. should select * users user_name = '$user_name' , password = '$password' , user_type == '$user_type'"
• you forgot = before user_type column.