从date中获取相应信息

CREATE OR REPLACE VIEW v AS
SELECT TO_DATE(‘2015-5-5 13:14:15‘, ‘YYYY-MM-DD HH24:MI:SS‘) AS c FROM DUAL;

SELECT * FROM v;

SELECT c,
       TO_CHAR(c, ‘hh24‘) 时,
       TO_CHAR(c, ‘mi‘) 分,
       TO_CHAR(c, ‘ss‘) 秒,
       TO_CHAR(c, ‘dd‘) 日,
       TO_CHAR(c, ‘mm‘) 月,
       TO_CHAR(c, ‘yyyy‘) 年,
       TO_CHAR(c, ‘ddd‘) 年内第几天,
       TRUNC(c, ‘dd‘) 一天之始,
       TRUNC(c, ‘day‘) 周初,
       TRUNC(c, ‘mm‘) 月初,
       LAST_DAY(c) 月末,
       ADD_MONTHS(TRUNC(c, ‘mm‘), 1) 下月初,
       TRUNC(c, ‘yyyy‘) 年初,
       TO_CHAR(c, ‘day‘) 周几,
       TO_CHAR(c, ‘month‘) 月份
  FROM v;