学习笔记

//解锁用户
alters user scott account unlock;

//解决查询  '
select ss || 'sssd''sdfsdf'  from ee;


//不重复显示已有的数据  distinct
select distinct depno from emp;

 

//查询空的值

select * from  emp where comn is null;

 

//查询非空值

select * from emp where comn is not null;

 

//查询日期

select ename,hiredate from emp where hiredate>'02-2月-1982'

 

//查看所有表格

select * from tab;

 

//查看所有储存过程

select * from user_source;