附件数据库 dept.dmp 用户名 mytestdb 密码 123
-- Create table
create table DEPT
(
DEPTNO NUMBER not null,
DNAME VARCHAR2(30),
LOC VARCHAR2(30)
)
tablespace USERS
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64
next 1
minextents 1
maxextents unlimited
);
-- Add comments to the columns
comment on column DEPT.DEPTNO
is '部门编号';
comment on column DEPT.DNAME
is '部门名称';
comment on column DEPT.LOC
is '地址';
-- Create/Recreate primary, unique and foreign key constraints
alter table DEPT
add constraint DEPTNO_KEY primary key (DEPTNO)
using index
tablespace USERS
pctfree 10
initrans 2
maxtrans 255
storage
(
initial 64K
next 1M
minextents 1
maxextents unlimited
);
-- Create table
create table EMP
(
EMPNO NUMBER not null,
ENAME VARCHAR2(20),
JOB VARCHAR2(30),
MGR NUMBER,
HIREDATE VARCHAR2(20),
SAL NUMBER,
COMM NUMBER,
DEPTNO NUMBER
)
tablespace USERS
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64
next 1
minextents 1
maxextents unlimited
);
-- Add comments to the columns
comment on column EMP.EMPNO
is '员工编号';
comment on column EMP.ENAME
is '员工名称';
comment on column EMP.JOB
is '工作';
comment on column EMP.MGR
is '领导编号';
comment on column EMP.HIREDATE
is '工作年限';
comment on column EMP.SAL
is '薪水';
comment on column EMP.DEPTNO
is '部门编号';
-- Create/Recreate primary, unique and foreign key constraints
alter table EMP
add constraint EMPNO_KEY primary key (EMPNO)
using index
tablespace USERS
pctfree 10
initrans 2
maxtrans 255
storage
(
initial 64K
next 1M
minextents 1
maxextents unlimited
);
alter table EMP
add constraint EMP_DOP_FK foreign key (DEPTNO)
references DEPT (DEPTNO) on delete cascade;
--使用相等链接 查询 员工名称 薪水 和 部门
select ename 员工名称,sal 薪水,dept.deptno 部门 from emp,dept where emp.deptno=dept.deptno
select ename 员工名称,sal 薪水,dept.deptno 部门编号,dept.dname from emp,dept where emp.deptno=dept.deptno and dept.deptno=10
--加and条件
select e.ename,d.loc from emp e,dept d where e.deptno=d.deptno and e.deptno=30
--自连接
select worker.ename||'''s manager is '|| manager.ename from emp worker,emp manager where worker.mgr=manager.empno
--不等连接
select * from emp f where f.sal between 1000 and 3000
select * from emp f where f.sal between f.sal and f.sal
--外连接
select dept.dname,emp.ename from dept,emp where dept.deptno=emp.deptno(+) and emp.deptno(+)=10
--Cross join链接 交叉
select d.deptno,e.ename from dept d cross join emp e
--Natural join链接 自然
select e.ename,e.sal,d.dname from dept d natural join emp e
--Natural join链接
--如果两张表具有多个同列名那么当建立natural join链接时。Oracle会基于多个同名列进行相等链接，如果只希望使用某个同名列执行相等连接那么需要使用using子句
select d.dname,e.ename from dept d join emp e using(deptno)
--On子句
select e.ename,e.sal,d.dname from emp e join dept d on e.deptno=d.deptno and e.deptno=10
--左链接 left join
select a.dname,e.ename from dept a left join emp e on a.deptno=e.deptno and a.deptno=10
--右链接 right join
select d.dname,e.ename from dept d right join emp e on d.deptno=e.deptno and d.deptno=10
select d.dname,e.ename from dept d , emp e where d.deptno(+)=e.deptno and d.deptno(+)=10