The following query:
select cdate from rprt where cdate <= TO_CHAR(sysdate, \'YYYY/MM/DD-HH24-MI-SS-SSSSS\') and ryg=\'R\' and cnum=\'C002\';
Use the function cast() to convert from timestamp to date
select to_char(cast(sysdate as date),'DD-MM-YYYY') from dual;
For more info of function cast oracle11g http://docs.oracle.com/cd/B28359_01/server.111/b28286/functions016.htm#SQLRF51256