Trying to get this Please Help

[BuildFrmScrch]

I am teaching myself from scratch. I am reading at w3schools and trying to apply it to a site for my friend that needs what I am finding to be an extremely complex site. It involves many users, events, and assigning users to the events, as well as if there is pay then the rate both for client and staff! This is my Log in execution Page. I have only ever made an HTML site. I really appreciate any advice. My queries are wrong and I am getting parse errors. I am using MySQL. Thank you!!

<?php include('database_connect.php'); ?>
<?php
$username = $_POST['user']; //---User Input Username utf8---\\
$password = $_POST['pass']; //---User Input Password utf8---\\
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);

$sql = mysql_num_rows(mysql_query('SELECT DISTINCT CONVERT(\"`Username` USING utf8\") FROM `AES_Users` WHERE (`Username`) = $username LIMIT 1'));
 ?>
<?php if('$sql = 0'){?>
<?php echo('Error! The username you specified does not exist\');?>
<?php
$row = mysql_query('SELECT DISTINCT CONVERT(\"`Username` USING utf8\") AND CONVERT(\"`Password` USING utf8\") AND CONVERT(\"`Permission` USING utf8\") FROM TABLE `AES_Users` WHERE (`Username`) = $username LIMIT 1'); 
$password2 = $row['CONVERT(`Password` USING utf8)'];
$permission = $row['CONVERT(`Permission` USING utf8)'];
$username2 = $row['CONVERT(`Permission` USING utf8)'];
$username = $_POST['user']; //---User Input Username utf8---\\
$password = $_POST['pass']; //---User Input Password utf8---\\
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);
?>

<?php } elseif('$username = $row[\"CONVERT(`Username` USING utf8)\"] AND $password = $row[\"CONVERT(`Password` USING utf8)\"] AND $row[\"CONVERT(`Permission` USING utf8)\"] = Admin\') {?>
<?php header("http://www.bella-epoque-cloisonne-jewelry.com/admin.php") ?>

<?php } elseif('$username = $row[\"CONVERT(`Username` USING utf8)\"] AND $password = $row[\"CONVERT(`Password` USING utf8)\"] AND $row[\"CONVERT(`Permission` USING utf8)\"] = Manager\') {?>
<?php header("http://www.bella-epoque-cloisonne-jewelry.com/manager.php") ?>

<?php } elseif('$username = $row[\"CONVERT(`Username` USING utf8)\"] AND $password = $row[\"CONVERT(`Password` USING utf8)\"] AND $row[\"CONVERT(`Permission` USING utf8)\"] = Client\') {?>
<?php header("http://www.bella-epoque-cloisonne-jewelry.com/clients.php") ?>

<?php } elseif('$username = $row[\"CONVERT(`Username` USING utf8)\"] AND $password = $row[\"CONVERT(`Password` USING utf8)\"] AND $row[\"CONVERT(`Permission` USING utf8)\"] = Staff\') {?>
<?php header("http://www.bella-epoque-cloisonne-jewelry.com/staff.php") ?>

<?php } elseif('$username = $row[\"CONVERT(`Username` USING utf8)\"] AND $password = $row[\"CONVERT(`Password` USING utf8)\"] AND $row[\"CONVERT(`Permission` USING utf8)\"] = DE\') {?>
<?php header(\"http://www.bella-epoque-cloisonne-jewelry.com/DE.php\") ?>

<?php } else('$password != $row[\"CONVERT(`Password` USING utf8)\"]\') ?>
<?php echo('Error! The username and password combination you entered does not match the ones we have in the database.\'); ?>

It does not work

[NogDog]

You have issues with your quotes. If you look at the color highlighting of your code now that it's in this forum's [noparse]

...

[/noparse] tags, you see blocks of PHP code that is all in red, indicating the parser thinks it's part of a quoted string. You need to be sure that string literals begun with a single quote are closed with a single quote, and the same for double quotes, while any literal quotes of the same type within the string are escaped with a back-slash. At a quick glance, I see one line where you escaped a closing quote, which means it does not, in fact, close the quote:

<?php echo('Error! The username you specified does not exist\');?>  // that back-slash does not belong there