Oracle SYSDATE

sysdate

SELECT '当前时间' AS 描述,
       TO_CHAR(SYSDATE, 'yyyy-mm-dd hh24:mi:ss') AS 时间
  FROM DUAL
UNION ALL
SELECT '1天前' AS 描述,
       TO_CHAR(SYSDATE - 1, 'yyyy-mm-dd hh24:mi:ss') AS 时间
  FROM DUAL
UNION ALL
SELECT '1小时前' AS 描述,
       TO_CHAR(SYSDATE - 1 / 24, 'yyyy-mm-dd hh24:mi:ss') AS 时间
  FROM DUAL
UNION ALL
SELECT '1分钟前' AS 描述,
       TO_CHAR(SYSDATE - 1 / (24 * 60), 'yyyy-mm-dd hh24:mi:ss') AS 时间
  FROM DUAL
UNION ALL
SELECT '1秒钟前' AS 描述,
       TO_CHAR(SYSDATE - 1 / (24 * 60 * 60), 'yyyy-mm-dd hh24:mi:ss') AS 时间
  FROM DUAL
-- 2019-11-29号执行以下 sql
-- SELECT  TRUNC(SYSDATE - 1) + 1, TRUNC(SYSDATE + 1) FROM dual
-- 2019/11/29	2019/11/30

打印结果

描述		时间
当前时间   2019-03-10 10:53:36
1天前     2019-03-09 10:53:36
1小时前    2019-03-10 09:53:36
1分钟前    2019-03-10 10:52:36
1秒钟前    2019-03-10 10:53:35