oracle中日期格式'yyyy-mm-dd'和'yyyymmdd'的區別__oracle

oracle中日期格式'yyyy-mm-dd'和'yyyymmdd'的區別  

對於年月日中"日"是個位的情況下,處理不一樣,'yyyymmdd'格式沒問題,而式'yyyy-mm-dd'格式則不行,請看:

SQL> alter session set nls_date_format = 'yyyy-mm-dd hh24:mi:ss';

Session altered.

SQL> select to_date('2007059','yyyy-mm-dd hh24:mi:ss') from dual;
select to_date('2007059','yyyy-mm-dd hh24:mi:ss') from dual
                 *
ERROR at line 1:
ORA-01861: literal does not match format string

SQL> select to_date('2007059','yyyy-mm-dd') from dual;
select to_date('2007059','yyyy-mm-dd') from dual
                 *
ERROR at line 1:
ORA-01861: literal does not match format string

SQL> select to_date('2007059','yyyymmdd')   from dual;

TO_DATE('2007059','
-------------------
2007-05-09 00:00:00