Trouble with PDO query + LEFT JOIN [closed]

Question

I'm having trouble with a specific query (PDO style) that selects 4 fields from a table with a simple condition : contact_type='a' , label_id = a value (number) and also it checks that the particular contact type ('a') is not blocked, meaning is not in myl_blocked_contacts table. I LEFT

$query = "SELECT myl_contacts.contact_id, mya_users.name, mya_users.city, mya_users.ext 
          from myl_contacts, mya_users, 
              LEFT JOIN myl_blocked_contacts 
          WHERE myl_contacts.contact_type='a' 
            AND myl_contacts.label_id=:id 
            AND (myl_blocked_contacts.contact_type!='a' 
             AND myl_blocked_contacts.contact_id!=mya_users.id)
         ";
                                            $result = $db->prepare($query);
                                            $result->bindValue(':id', $_id, PDO::PARAM_INT);
                                            $result->execute();