Oracle 时间戳 日期

--秒级时间戳
SELECT (SYSDATE - TO_DATE('1970-1-1 8', 'YYYY-MM-DD HH24')) * 86400 FROM DUAL;
--毫秒级时间戳
SELECT (SYSDATE - TO_DATE('1970-1-1 8', 'YYYY-MM-DD HH24')) * 86400000 + TO_NUMBER(TO_CHAR(SYSTIMESTAMP(3), 'FF')) AS MILLIONS FROM DUAL;
--时间戳转日期
SELECT TO_CHAR(1509984000000 / (1000 * 60 * 60 * 24) +  
       TO_DATE('1970-01-01 08:00:00', 'YYYY-MM-DD HH:MI:SS'), 'YYYY-MM-DD HH:MI:SS') AS CDATE,
       TO_CHAR(1509465600000 / (1000 * 60 * 60 * 24) +  
       TO_DATE('1970-01-01 08:00:00', 'YYYY-MM-DD HH:MI:SS'), 'YYYY-MM-DD HH:MI:SS') AS CDATE,
       TO_CHAR(1509465600 / (60 * 60 * 24) +  
       TO_DATE('1970-01-01 08:00:00', 'YYYY-MM-DD HH:MI:SS'), 'YYYY-MM-DD HH:MI:SS') AS CDATE
FROM dual t;