MySQL Error

SELECT Id FROM i_carbon_photo WHERE (parentclass='') AND (parentprop='') AND (parentid='') AND ((pos < ) OR ((pos = ) AND (Id < 658))) ORDER BY pos DESC, Id DESC LIMIT 1
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ') OR ((pos = ) AND (Id < 658))) ORDER BY pos DESC, Id DESC LIMIT 1' at line 3