PHP login with PDO, doesnt seem to work -

there aren't errors given, reason code doesnt seem work..

here code:

<?php  session_start();  require_once('inc/db.php');  if(isset($_session['username'])) {     header("location: index.php"); } else {     try {         $username = mysql_real_escape_string($_post['username']);         $password = mysql_real_escape_string($_post['password']);          $sql = $dbh->prepare('select * users username =:username , password =:password');         $sql->bindparam(':username', $username);         $sql->bindparam(':password', $password);         $sql->execute();         $total = $sql->rowcount();         $row = $sql->fetch();          if($total > 0) {             if($row['verified'] > 0) {                 $_session['username'] = $username;             } else {                 echo "unverified";             }         } else {             echo "incorrect";         }     } catch(pdoexception $e) {      } }  ?> 

can me see what's wrong? thank lot in advance :)

edit::::

here db.php

<?php try {     $db_name = 'users';     $db_user = 'root';     $db_pass = '';     $dbh = new pdo('mysql:host=localhost;dbname='.$db_name, $db_user, $db_pass, array(pdo::mysql_attr_init_command => "set names utf8"));     $dbh->setattribute(pdo::attr_errmode, pdo::errmode_exception); } catch(pdoexception $e) {     echo "error?"; } ?> 

this should serve better , identify errors if , when occur

<?php // inc/db.php  $dbh = new pdo('mysql:host=localhost;dbname=users;charset=utf8', 'root', ''); $dbh->setattribute(pdo::attr_errmode, pdo::errmode_exception); $dbh->setattribute(pdo::attr_emulate_prepares, false); 

and main file

<?php // remove these 2 lines when you've finished development ini_set('display_errors', 'on'); error_reporting(e_all);  session_start();  if (isset($_session['username'])) {     header("location: index.php");     exit; }  if (!isset($_post['username'], $_post['password'])) {     throw new runtimeexception('required post parameters not present'); }  require_once __dir__ . '/inc/db.php';  $sql = $dbh->prepare('select * users username = :username , password = :password'); $sql->bindparam(':username', $_post['username']); $sql->bindparam(':password', $_post['password']); $sql->execute(); $row = $sql->fetch(pdo::fetch_assoc);  if ($row !== false) {     if ($row['verified'] > 0) {         $_session['username'] = $username;         // want redirect here or     } else {         echo 'unverified';     } } else {     echo "incorrect"; }