oracle抽取函数 extract()
auhtor：skate
time：2010/03/03
oracle抽取函数
今天朋友问个问题，如何抽取时间的“小时”
oracle的抽取函数是 extrac()语法:
SELECT EXTRACT(YEAR from SYSDATE) from DUAL; return Current Year
SELECT EXTRACT(MONTH from SYSDATE) from DUAL; return Current Month
SELECT EXTRACT(DAY from SYSDATE) from DUAL; return Current Day
SELECT EXTRACT(HOUR from TIMESTAMP '2010-10-10 10:10:10') from DUAL;
SELECT EXTRACT(MINUTE from TIMESTAMP '2010-10-10 10:10:10') from DUAL;
例子如下：
SQL> SELECT EXTRACT(YEAR from SYSDATE) from DUAL
2 ;
EXTRACT(YEARfromSYSDATE)
------------------------
2010
SQL> SELECT EXTRACT(month from SYSDATE) from DUAL
2 ;
EXTRACT(MONTHfromSYSDATE)
-------------------------
3
SQL> SELECT EXTRACT(day from SYSDATE) from DUAL;
EXTRACT(DAYfromSYSDATE)
-----------------------
3
SQL> SELECT EXTRACT(hour from SYSDATE) from DUAL;
SELECT EXTRACT(hour from SYSDATE) from DUAL
ORA-30076: 对析出来源无效的析出字段
SQL> SELECT EXTRACT(minute from SYSDATE) from DUAL;
SELECT EXTRACT(minute from SYSDATE) from DUAL
ORA-30076: 对析出来源无效的析出字段
SQL> SELECT EXTRACT(HOUR from TIMESTAMP '2010-10-10 10:10:10') from DUAL;
EXTRACT(HOURfromTIMESTAMP'2010
------------------------------
10
SQL> SELECT EXTRACT(minute from TIMESTAMP '2010-10-10 10:10:10') from DUAL;
EXTRACT(MINUTEfromTIMESTAMP'20
------------------------------
相关文档：
转自： http://blog.csdn.net/kongqz/archive/2009/05/15/4184415.aspx
就是在已有的数据库实例上创建一个新的帐号，访问一些新的表
操作步骤如下：
1、登录linux，以oracle用户登录（如果是root用户登录的，登录后用 su - oracle命令切换成oracle用户）
2、以sysdba方式来打开sqlplus，命令如下： s ......
一．简单SQL查询：
1）:统计每个部门员工的数目
select dept,count(*) from employee group by dept;
2）:统计每个部门员工的数目大于一个的记录
select dept,count(*) from employee group by dept having count(*)>1;
3）:统计工资超过1200的员工所在部门的名称
select e.first_name,salary,d.name
from s_emp ......
using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using Syste ......
一、忘记除SYS、SYSTEM用户之外的用户的登录密码。
用SYS (或SYSTEM)用户登录。
CONN SYS/PASS_WORD AS SYSDBA;
使用如下语句修改用户的密码。
ALTER USER user_name IDENTIFIED BY newpass;
......
