페이징 처리 쿼리

SELECT *
 FROM
    (SELECT rownum as rnum, userId, userName, userPhone, userEmail, classFlag, groupFlag, useFlag, registDate
     FROM
       (
    select userId, userName, userPhone, userEmail, classFlag, groupFlag, useFlag, registDate from studio.customer_mng where useFlag='Y' order by idx DESC, userName
    )  )
 WHERE rnum > 0 AND rownum <= 10