ORACLE日期时间函数大全.doc

ORACLE日期时间函数大全 ?? TO_DATE格式(以时间:2007-11-02?? 13:45:25为例)?? ??????? Year:????? ??????? yy two digits 两位年??????????????? 显示值:07??????? yyy three digits 三位年??????????????? 显示值:007??????? yyyy four digits 四位年??????????????? 显示值:2007??????????? ??????? Month:????? ??????? mm??? number???? 两位月????????????? 显示值:11??????? mon??? abbreviated 字符集表示????????? 显示值:11月,若是英文版,显示nov???? ??????? month spelled out 字符集表示????????? 显示值:11月,若是英文版,显示november ????????? ??????? Day:????? ??????? dd??? number???????? 当月第几天??????? 显示值:02??????? ddd??? number???????? 当年第几天??????? 显示值:02??????? dy??? abbreviated 当周第几天简写??? 显示值:星期五,若是英文版,显示fri??????? day??? spelled out?? 当周第几天全写??? 显示值:星期五,若是英文版,显示friday??????? ??????? ddspth spelled out, ordinal twelfth ???????????? ????????????? Hour:????????????? hh??? two digits 12小时进制??????????? 显示值:01????????????? hh24 two digits 24小时进制??????????? 显示值:13????????????? ????????????? Minute:????????????? mi??? two digits 60进制??????????????? 显示值:45????????????? ????????????? Second:????????????? ss??? two digits 60进制??????????????? 显示值:25????????????? ????????????? 其它????????????? Q???? digit???????? 季度????????????????? 显示值:4????????????? WW??? digit???????? 当年第几周??????????? 显示值:44????????????? W??? digit????????? 当月第几周??????????? 显示值:1????????????? ??????? 24小时格式下时间范围为： 0:00:00 - 23:59:59....????? ??????? 12小时格式下时间范围为： 1:00:00 - 12:59:59 .... ??????????? 1. 日期和字符转换函数用法（to_date,to_char）???????? select to_char(sysdate,yyyy-mm-dd hh24:mi:ss) as nowTime from dual;?? //日期转化为字符串?? select to_char(sysdate,yyyy) as nowYear?? from dual;?? //获取时间的年?? select to_char(sysdate,mm)??? as nowMonth from dual;?? //获取时间的月?? select to_char(sysdate,dd)??? as nowDay??? from dual;?? //获取时间的日?? select to_char(sysdate,hh24) as nowHour?? from dual;?? //获取时间的时?? select to_char(sysdate,mi)??? as nowMinute from dual;?? //获取时间的分?? select to_char(sysdate,ss)??? as nowSecond from dual;?? //获取时间的秒 ??? select to_date(2004-05-07 13:23:44,yyyy-mm-d