MySql query error near WHERE

My code is

$user_query = '
      UPDATE  
           users  
      SET  
           `password`="$password",  
           `email`="$email", 
           `position`="$position", 
      WHERE  
           `username`=".$uname."';
 $user_result = mysql_query($user_query, $connection);
 confirm_query($user_result);
 

When I run this query it gives me a error saying

Database query failed: You have an error in your SQL syntax;
 check the manual that corresponds to your MySQL server version for the right syntax to use near
 'WHERE `username`=".$uname."' at line 7
 

Can any body help me on this error. thank you everyone.?

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