经典Oracle表。包括联接查询示例。

Statement1

创建DEPT表，该表将是EMP表的父表。

create table dept(  
  deptno     number(2,0),  
  dname      varchar2(14),  
  loc        varchar2(13),  
  constraint pk_dept primary key (deptno)  
)

Table created.

Statement2

创建EMP表，该表具有对DEPT表的外键引用。外键将要求EMP表中的DEPTNO存在于DEPT表的DEPTNO列中。

create table emp(  
  empno    number(4,0),  
  ename    varchar2(10),  
  job      varchar2(9),  
  mgr      number(4,0),  
  hiredate date,  
  sal      number(7,2),  
  comm     number(7,2),  
  deptno   number(2,0),  
  constraint pk_emp primary key (empno),  
  constraint fk_deptno foreign key (deptno) references dept (deptno)  
)

Table created.

Statement3

使用命名列将行插入DEPT表。

insert into DEPT (DEPTNO, DNAME, LOC)
values(10, 'ACCOUNTING', 'NEW YORK')

1 row(s) inserted.

Statement4

按列位置在DEPT表中插入一行。

insert into dept  
values(20, 'RESEARCH', 'DALLAS')

1 row(s) inserted.

Statement5

insert into dept  
values(30, 'SALES', 'CHICAGO')

1 row(s) inserted.

Statement6

insert into dept  
values(40, 'OPERATIONS', 'BOSTON')

1 row(s) inserted.

Statement7

插入EMP行，使用TO_DATE函数将字符串文字转换为oracle日期格式。

insert into emp  
values(  
 7839, 'KING', 'PRESIDENT', null,  
 to_date('17-11-1981','dd-mm-yyyy'),  
 5000, null, 10  
)

1 row(s) inserted.

Statement8

insert into emp  
values(  
 7698, 'BLAKE', 'MANAGER', 7839,  
 to_date('1-5-1981','dd-mm-yyyy'),  
 2850, null, 30  
)

1 row(s) inserted.

Statement9

insert into emp  
values(  
 7782, 'CLARK', 'MANAGER', 7839,  
 to_date('9-6-1981','dd-mm-yyyy'),  
 2450, null, 10  
)

1 row(s) inserted.

Statement10

insert into emp  
values(  
 7566, 'JONES', 'MANAGER', 7839,  
 to_date('2-4-1981','dd-mm-yyyy'),  
 2975, null, 20  
)

1 row(s) inserted.

Statement11

insert into emp  
values(  
 7788, 'SCOTT', 'ANALYST', 7566,  
 to_date('13-JUL-87','dd-mm-rr') - 85,  
 3000, null, 20  
)

1 row(s) inserted.

Statement12

insert into emp  
values(  
 7902, 'FORD', 'ANALYST', 7566,  
 to_date('3-12-1981','dd-mm-yyyy'),  
 3000, null, 20  
)

1 row(s) inserted.

Statement13

insert into emp  
values(  
 7369, 'SMITH', 'CLERK', 7902,  
 to_date('17-12-1980','dd-mm-yyyy'),  
 800, null, 20  
)

1 row(s) inserted.

Statement14

insert into emp  
values(  
 7499, 'ALLEN', 'SALESMAN', 7698,  
 to_date('20-2-1981','dd-mm-yyyy'),  
 1600, 300, 30  
)

1 row(s) inserted.

Statement15

insert into emp  
values(  
 7521, 'WARD', 'SALESMAN', 7698,  
 to_date('22-2-1981','dd-mm-yyyy'),  
 1250, 500, 30  
)

1 row(s) inserted.

Statement16

insert into emp  
values(  
 7654, 'MARTIN', 'SALESMAN', 7698,  
 to_date('28-9-1981','dd-mm-yyyy'),  
 1250, 1400, 30  
)

1 row(s) inserted.

Statement17

insert into emp  
values(  
 7844, 'TURNER', 'SALESMAN', 7698,  
 to_date('8-9-1981','dd-mm-yyyy'),  
 1500, 0, 30  
)

1 row(s) inserted.

Statement18

insert into emp  
values(  
 7876, 'ADAMS', 'CLERK', 7788,  
 to_date('13-JUL-87', 'dd-mm-rr') - 51,  
 1100, null, 20  
)

1 row(s) inserted.

Statement19

insert into emp  
values(  
 7900, 'JAMES', 'CLERK', 7698,  
 to_date('3-12-1981','dd-mm-yyyy'),  
 950, null, 30  
)

1 row(s) inserted.

Statement20

insert into emp  
values(  
 7934, 'MILLER', 'CLERK', 7782,  
 to_date('23-1-1982','dd-mm-yyyy'),  
 1300, null, 10  
)

1 row(s) inserted.

Statement21

基于DEPT表DEPTNO的主键和EMP表中的DEPTNO外键，DEPT表与EMP表之间的简单自然连接。

select ename, dname, job, empno, hiredate, loc  
from emp, dept  
where emp.deptno = dept.deptno  
order by ename

14 rows selected.

Statement22

SQL语句中的GROUP BY子句允许聚合非分组列的函数。联接是内部联接，因此不显示没有员工

的部门。

select dname, count(*) count_of_employees
from dept, emp
where dept.deptno = emp.deptno
group by DNAME
order by 2 desc