SELECT TRUNC(TRUNC(SYSDATE-1,

SELECT TRUNC(TRUNC(SYSDATE-1, 'YEAR')-1, 'YEAR') FROM DUAL -- Get first day of last year, sysdate-1 indicate current day in DW case.

select add_months(trunc(sysdate, 'year'), 12) - (1 / 800) from dual -- 得到当年最后一天最后时刻分秒。

SELECT TRUNC(TO_DATE('20110228', 'YYYYMMDD'), 'MONTH') AS FIRST_DAY_MONTH FROM DUAL --- 获取当前月的第一天

SELECT TRUNC(SYSDATE, 'MONTH') AS FIRST_DAY_CURRENT_MONTH FROM DUAL; -- 得系统当月第一天

--- 获得去年的上个月第一天到今年的上个月的最后一天的最后时间点。如当前为2011-09，，则返回2010-08-01 至2011-08-31 23:59:59

SELECT TRUNC(ADD_MONTHS(SYSDATE, -13), 'MONTH'), -- fist_day_of_previous_month_of_last_year

TRUNC(SYSDATE, 'MONTH') - (1 / 800) -- end_datetime_of_last_month

FROM DUAL;

SELECT TRUNC(SYSDATE, 'MONTH') - (1 / 800)FROM DUAL; -- 得系统上个月最后一天最后时间点

--- 获取指定月的上上一个月的起止日期段。

SELECT TRUNC(ADD_MONTHS(SYSDATE, -2), 'MONTH') AS fisrt_day_of_last_last_month,

Trunc(ADD_MONTHS(SYSDATE, -1), 'MONTH') - (1 / 800) AS Last_Day_of_last_Last_Month

FROM DUAL;

SELECT TRUNC(ADD_MONTHS(to_date('20110220', 'yyyymmdd'), -2), 'MONTH') AS fisrt_day_of_last_last_month,

Trunc(ADD_MONTHS(to_date('20110220', 'yyyymmdd'), -1), 'MONTH') - (1 / 800) AS Last_Day_of_last_Last_Month

FROM DUAL;

--- 获取上一天最后时刻点的二个方法

select (TRUNC(NEXT_DAY(SYSDATE, 1), 'DAY') - (1 / 800)) - 3 from dual;

SELECT TO_DATE(TO_CHAR(SYSDATE, 'YYYY-MM-DD'), 'YYYY-MM-DD') - (1 / 800) FROM DUAL;