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oracle 日期函数

Jun 07, 2016 pm 06:03 PM

oracle 日期函数

正在看的ORACLE教程是:oracle 日期函数。

在oracle中有很多关于日期的函数,

如:

1、add_months()用于从一个日期值增加或减少一些月份 date_value:=add_months(date_value,number_of_months) 例: SQL> select add_months(sysdate,12) Next Year from dual; Next Year ---------- 13-11月-04 SQL> select add_months(sysdate,112) Last Year from dual; Last Year ---------- 13-3月 -13 SQL>

2、current_date()返回当前会放时区中的当前日期 date_value:=current_date SQL> column sessiontimezone for a15 SQL> select sessiontimezone,current_date from dual; SESSIONTIMEZONE CURRENT_DA --------------- ---------- +08:00 13-11月-03 SQL> alter session set time_zone=-11:00 2 / 会话已更改。 SQL> select sessiontimezone,current_timestamp from dual; SESSIONTIMEZONE CURRENT_TIMESTAMP --------------- ------------------------------------ -11:00 12-11月-03 04.59.13.668000 下午 -11: 00 SQL>

3、current_timestamp()以timestamp with time zone数据类型返回当前会放时区中的当前日期 timestamp_with_time_zone_value:=current_timestamp([timestamp_precision]) SQL> column sessiontimezone for a15 SQL> column current_timestamp format a36 SQL> select sessiontimezone,current_timestamp from dual; SESSIONTIMEZONE CURRENT_TIMESTAMP --------------- ------------------------------------ +08:00 13-11月-03 11.56.28.160000 上午 +08: 00 SQL> alter session set time_zone=-11:00 2 / 会话已更改。 SQL> select sessiontimezone,current_timestamp from dual; SESSIONTIMEZONE CURRENT_TIMESTAMP --------------- ------------------------------------ -11:00 12-11月-03 04.58.00.243000 下午 -11: 00 SQL>

4、dbtimezone()返回时区 varchar_value:=dbtimezone SQL> select dbtimezone from dual; DBTIME ------ -07:00 SQL>

5、extract()找出日期或间隔值的字段值 date_value:=extract(date_field from [datetime_value|interval_value]) SQL> select extract(month from sysdate) This Month from dual; This Month ---------- 11 SQL> select extract(year from add_months(sysdate,36)) 3 Years Out from dual; 3 Years Out ----------- 2006  

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正在看的ORACLE教程是:oracle 日期函数。;SQL>

6、last_day()返回包含了日期参数的月份的最后一天的日期 date_value:=last_day(date_value) SQL> select last_day(date2000-02-01) Leap Yr? from dual; Leap Yr? ---------- 29-2月 -00 SQL> select last_day(sysdate) Last day of this month from dual; Last day o ---------- 30-11月-03 SQL>

7、localtimestamp()返回会话中的日期和时间 timestamp_value:=localtimestamp SQL> column localtimestamp format a28 SQL> select localtimestamp from dual; LOCALTIMESTAMP ---------------------------- 13-11月-03 12.09.15.433000 下午 SQL> select localtimestamp,current_timestamp from dual; LOCALTIMESTAMP CURRENT_TIMESTAMP ---------------------------- ------------------------------------ 13-11月-03 12.09.31.006000 13-11月-03 12.09.31.006000 下午 +08: 下午 00 SQL> alter session set time_zone=-11:00; 会话已更改。 SQL> select localtimestamp,to_char(sysdate,DD-MM-YYYY HH:MI:SS AM) SYSDATE from dual; LOCALTIMESTAMP SYSDATE ---------------------------- ------------------------ 12-11月-03 05.11.31.259000 13-11-2003 12:11:31 下午 下午 SQL>

8、months_between()判断两个日期之间的月份数量 number_value:=months_between(date_value,date_value) SQL> select months_between(sysdate,date1971-05-18) from dual; MONTHS_BETWEEN(SYSDATE,DATE1971-05-18) ---------------------------------------- 389.855143 SQL> select months_between(sysdate,date2001-01-01) from dual; MONTHS_BETWEEN(SYSDATE,DATE2001-01-01) ---------------------------------------- 34.4035409 SQL>

9、next_day()给定一个日期值,返回由第二个参数指出的日子第一次出现在的日期值(应返回相应日子的名称字符串) 本文参考oracle中国联盟

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