为了便利学习和测试，所有的例子都是在Oracle自带用户Scott下树立的。
create table EMP
(
empno NUMBER(4) not null,
ename VARCHAR2(10),
job VARCHAR2(9),
mgr NUMBER(4),
hiredate DATE,
sal NUMBER(7,2),
comm NUMBER(7,2),
deptno NUMBER(2)
)
alter table EMP
add constraint PK_EMP primary key (EMPNO);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7369, "SMITH", "CLERK", 7902, to_date("17-12-1980", "dd-mm-yyyy"), 800, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7499, "ALLEN", "SALESMAN", 7698, to_date("20-02-1981", "dd-mm-yyyy"), 1600, 300, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7521, "WARD", "SALESMAN", 7698, to_date("22-02-1981", "dd-mm-yyyy"), 1250, 500, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7566, "JONES", "MANAGER", 7839, to_date("02-04-1981", "dd-mm-yyyy"), 2975, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7654, "MARTIN", "SALESMAN", 7698, to_date("28-09-1981", "dd-mm-yyyy"), 1250, 1400, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7698, "BLAKE", "MANAGER", 7839, to_date("01-05-1981", "dd-mm-yyyy"), 2850, null, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7782, "CLARK", "MANAGER", 7839, to_date("09-06-1981", "dd-mm-yyyy"), 2450, null, 10);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7788, "SCOTT", "ANALYST", 7566, to_date("19-04-1987", "dd-mm-yyyy"), 3000, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7839, "KING", "PRESIDENT", null, to_date("17-11-1981", "dd-mm-yyyy"), 5000, null, 10);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7844, "TURNER", "SALESMAN", 7698, to_date("08-09-1981", "dd-mm-yyyy"), 1500, 0, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7876, "ADAMS", "CLERK", 7788, to_date("23-05-1987", "dd-mm-yyyy"), 1100, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7900, "JAMES", "CLERK", 7698, to_date("03-12-1981", "dd-mm-yyyy"), 950, null, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7902, "FORD", "ANALYST", 7566, to_date("03-12-1981", "dd-mm-yyyy"), 3000, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7934, "MILLER", "CLERK", 7782, to_date("23-01-1982", "dd-mm-yyyy"), 1300, null, 10);
create ta
