Ошибка бд

DATABASE ERROR: 
SELECT con.*,
                       con.pubdate as fdate,
                       u.nickname as author,
                       u.login as author_login
                       FROM cms_content con
				       LEFT JOIN cms_category cat ON cat.id = con.category_id
				       LEFT JOIN cms_users u ON u.id = con.user_id
                       WHERE con.published = 1 AND con.showlatest = 1
                      AND (con.is_end=0 OR (con.is_end=1 AND con.enddate >= '2011-04-28 21:14:05' AND con.pubdate <= '2011-04-28 21:14:05'))
                      AND (cat.NSLeft >=  AND cat.NSRight <= )
				ORDER BY con.id DESC
				LIMIT 4You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND cat.NSRight <= ) ORDER BY con.id DESC LIMIT 4' at line 10