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--创建视图
原始数据 复制代码
create or replace view view_emp as select * from emp;
create or replace view view_emp_dep as select e.*,dep.dname from emp e
left join dept dep on e.deptno=dep.deptno
select * from view_emp
select * from view_emp_dep
--创建序列
原始数据 复制代码
create sequence seq_fjl
insert into emp(empno,ename) values(seq_fjl.nextval,'fjl')
select seq_fjl.nextval from dual
select seq_fjl.currval from dual
select * from emp
--创建索引
原始数据 复制代码
create table emp1 (
eno varchar(50) primary key,ename varchar(50)
)
create index index_ename1 on emp1(ename)
select * from emp1
select * from user_tables
select * from emp e where e.id in (select )
select *from employees

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