rman中如何制定删除某段时间的归档日志

eg：
RMAN> sql 'alter session set nls_date_format="YYYY-MM-DD"';

sql statement: alter session set nls_date_format="YYYY-MM-DD"

RMAN> delete archivelog from time "2012-12-01" until time "2013-02-28";

released channel: ORA_DISK_1

allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=144 devtype=DISK
specification does not match any archive log in the recovery catalog

小结：
sql 'alter session set nls_date_format="YYYY-MM-DD"';
delete archivelog from time "2012-12-01" until time "2013-02-28";