oracle：修改表的内容

一：insert
1.从一个表向另一个表复制行

insert into temp2 (id, month ,year, amount) select 10, month, year, amountfrom tempwhere id = 1;

二：RETURNING
returning子句返回聚合函数的计算结果

variable amount_temp numberupdate temp2set amount = amount * 2returning sum(amount) into :amount_tempprint amount_tempAMOUNT_TEMP-------------240

三：数据库事务
要永久性的记录事务，需要提交commit语句。
事务结束：
1.commit和rollback语句
2.执行DDL语句
3.执行一条DCL语句
4.断开与数据库的连接
四:查询闪回
使用dbms_flashBack
错误的提交了修改操作，并想查看各行原来的值。

CONNECT sys/change_on_install as sysdbagrant execute on sys.dbms_flashback to store;

connect store/store_passwordselect type, month, year，amountfrom temp2where year = '2017';TYPE　MONTH YEAR AMOUNT--------------------------1 1 2017 240

update temp2set amount = amount / 2select type, month, year，amountfrom temp2where year = '2017';TYPE　MONTH YEAR AMOUNT--------------------------1 1 2017 120

--查询10分钟之前的状态execute dbms_flashback.enable_at_time(sysdate - 10/1440)connect store/store_passwordselect type, month, year，amountfrom temp2where year = '2017';TYPE　MONTH YEAR AMOUNT--------------------------1 1 2017 240

禁用闪回操作：

execute dbms_flashBack.disable();

select type, month, year，amountfrom temp2where year = '2017';TYPE　MONTH YEAR AMOUNT--------------------------1 1 2017 120