oracle相关知识

1. 给表字段添加注释的语法

comment on  column 表名.字段名  is '注释信息';

2. 数据库字段重命名

alter table ORGAN_PARTER_EXT_TWO rename column balance_AccountOpen_Name_ZX to balance_Account_Open_Name_ZX;
comment on column ORGAN_PARTER_EXT_TWO.balance_Account_Open_Name_ZX is '投资者结算账户开户行-中信';

3. 数据库解除表锁定

-- 查看锁定的表
SELECT sess.sid,
         sess.serial#,
         lo.oracle_username,
         lo.os_user_name,
         ao.object_name,
         lo.locked_mode
FROM v$locked_object lo, dba_objects ao, v$session sess
WHERE ao.object_id = lo.object_id
        AND lo.session_id = sess.sid;

-- 根据Sid 和 Serial 解除锁定
alter system kill  session '915,58193'

4. 日期相减获取差值秒数

select TO_NUMBER(to_date(to_char(sysdate,'yyyy-MM-dd hh24:mi:ss'),'yyyy-MM-dd hh24:mi:ss')

- to_date('2013-01-16 00:00:00','yyyy-MM-dd hh24:mi:ss'))*24*60*60 from dual