select * from dt where dw_data=to_date(to_char(sysdate-1,'YYYY-MM-DD'),'YYYY-MM-DD') ---取前一天日期
SQL> select * from dt where dw_data=trunc(sysdate-1,'dd');
DW_DATA
---------
25-DEC-00
SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
SQL> select trunc(sysdate) from dual;
TRUNC(SYSDATE)
-------------------
2000-12-26 00:00:00
SQL> select trunc(sysdate,'dd') from dual;
TRUNC(SYSDATE,'DD')
-------------------
2000-12-26 00:00:00
SQL> select sysdate from dual;
SYSDATE
-------------------
2000-12-26 19:42:39
SQL> select * from dt;
DW_DATA
-------------------
2000-12-25 00:00:00
