not exists 和not in

SELECT * FROM TUSER t1
where  not exists (SELECT 1 FROM (
 select mobile from APP_T_INFO where PASSDATE>to_date('2015-08-20','yyyy-mm-dd')
 )t2 where t1.mobilenum = t2.mobile ) and t1.creationtime>to_date('2015-08-20','yyyy-mm-dd')  
 ;