數據庫練習題一答案

習題

https://blog.csdn.net/zixing08/article/details/102963362

建表

create table BONUS
(
ename VARCHAR(10),
job VARCHAR(9),
sal numeric(8,2),
comm numeric(8,2)
);

create table DEPT
(
deptno int not null,
dname VARCHAR(14),
loc VARCHAR(23)
);
alter table DEPT
add constraint PK_DEPT primary key (DEPTNO);

–=====================
create table EMP
(
empno int not null,
ename VARCHAR(20),
job VARCHAR(20),
mgr int,
hiredate DATE,
sal numeric(7,2),
comm numeric(7,2),
deptno int
);
alter table EMP
add constraint PK_EMP primary key (EMPNO);
alter table EMP
add constraint FK_DEPTNO foreign key (DEPTNO)
references DEPT (DEPTNO);
alter table emp drop foreign key FK_DEPTNO;

create table SALGRADE
(
grade numeric(7,2),
losal numeric(7,2),
hisal numeric(7,2)
);

插入數據

insert into DEPT (deptno, dname, loc)
values (10, ‘ACCOUNTING’, ‘NEW YORK’);
insert into DEPT (deptno, dname, loc)
values (20, ‘RESEARCH’, ‘DALLAS’);
insert into DEPT (deptno, dname, loc)
values (30, ‘SALES’, ‘CHICAGO’);
insert into DEPT (deptno, dname, loc)
values (40, ‘OPERATIONS’, ‘BOSTON’);

insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7369, ‘SMITH’, ‘CLERK’, 7902, ‘1980-12-17’, 1100, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7499, ‘ALLEN’, ‘SALESMAN’, 7698,‘1981-2-20’, 1760, 300, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7521, ‘WARD’, ‘SALESMAN’, 7698, ‘1981-02-22’, 1375, 500, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7566, ‘JONES’, ‘MANAGER’, 7839, ‘1981-04-02’, 3272, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7654, ‘MARTIN’, ‘SALESMAN’, 7698, ‘1981-09-28’, 1375, 1400, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7698, ‘BLAKE’, ‘MANAGER’, 7839, ‘1981-05-01’, 3135, null, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7782, ‘CLARK’, ‘MANAGER’, 7839, ‘1981-06-09’, 2695, null, 10);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7788, ‘SCOTT’, ‘ANALYST’, 7566, ‘1987-04-19’, 3000, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7839, ‘KING’, ‘PRESIDENT’, null, ‘1981-11-17’, 5500, null, 10);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7844, ‘TURNER’, ‘SALESMAN’, 7698, ‘1981-09-08’, 1650, 0, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7876, ‘ADAMS’, ‘CLERK’, 7788, ‘1987-05-23’, 1100, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7900, ‘JAMES’, ‘CLERK’, 7698, ‘1981-12-03’, 1045, null, 30);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7902, ‘FORD’, ‘ANALYST’, 7566, ‘1981-12-03’, 3300, null, 20);
insert into EMP (empno, ename, job, mgr, hiredate, sal, comm, deptno)
values (7934, ‘MILLER’, ‘CLERK’, 7782, ‘1982-01-23’, 1430, null, 10);
commit;

insert into SALGRADE (grade, losal, hisal)
values (1, 700, 1200);
insert into SALGRADE (grade, losal, hisal)
values (2, 1201, 1400);
insert into SALGRADE (grade, losal, hisal)
values (3, 1401, 2000);
insert into SALGRADE (grade, losal, hisal)
values (4, 2001, 3000);
insert into SALGRADE (grade, losal, hisal)
values (5, 3001, 9999);
commit;

查詢

select * from dept;
select * from salgrade;

–顯示僱員姓名，根據其服務年限，將最老的僱員排在最前面
SELECT ename,HIREDATE FROM EMP ORDER BY HIREDATE ASC;

–找出在（任何年份的）2月受聘的所有僱員
select * from EMP where substring(hiredate,6,2)=‘02’

select * from emp where date_format(hiredate,’%m’)=‘02’;

–找出所有的普通員工
SELECT * FROM EMP WHERE EMPNO NOT IN ( SELECT MGR FROM EMP WHERE MGR is NOT NULL)

–求出每個部門的平均工資，及它的等級
Select t.deptno,t.avg_sal,s.GRADE
FROM
(select AVG(SAL) avg_sal,DEPTNO from EMP GROUP BY DEPTNO)t
inner join SALGRADE s ON t.avg_sal BETWEEN s.LOSAL AND s.HISAL;

–求平均薪水最高的部門的部門編號
Select deptno,avg_sal
from (select avg(sal) avg_sal,deptno from emp group by deptno) t
where t.avg_sal = (select max(d.avg_sal) from
(select avg(sal) avg_sal,deptno from emp group by deptno) d);

–給任職日期超過35年的人加薪10%；
update emp set sal=sal*1.1 where date_add(hiredate,interval 35 year)<now()
–JDBC實現的代碼省略