ORACLE关于日期的查询

1.获取当前时间

select to_char(sysdate,'yyyy-mm-dd') datadate from dual;

2.获取当前年份第一天

select to_char(trunc(sysdate,'yyyy'),'yyyy-mm-dd') datadate from dual;

3.获取当前年份最后一天

select to_char(add_months(trunc(sysdate,'yyyy'),12)-1,'yyyy-mm-dd') datadate from dual;

4.获取3年前的第一天

select to_char(add_months(trunc(sysdate,'yyyy'),-12*2),'yyyy-mm-dd') datadate from dual;

5.获取明年今天

select to_char(add_months(sysdate,12),'yyyy-mm-dd') datadate from dual;

6.获取去年今天

select to_char(add_months(sysdate,-12),'yyyy-mm-dd') datadate from dual;