oracle练习题（二）

1、列出所有办事员的姓名、编号和部门

select ename,empno,dname from dept,emp where emp.deptno=dept.deptno

2、找出部门10中所有经理和部门20中的所有办事员的详细资料

select * from emp where (deptno=10 and job='MANAGER') or (deptno=20  and job='CLERK')

3、找出部门10中所有经理、部门20中所有办事员，既不是经理又不是办事员但其薪金>=2000的所有雇员的详细资料

select * from emp where deptno =10 and job='MANAGER' UNION select * from emp where deptno =20 and job='CLERK' UNION SELECT * FROM EMP WHERE JOB NOT IN('MANAGER' ,'CLERK') AND SAL>=2000     select * from emp where (deptno=10 and job='MANAGER') or (deptno=20  and job='CLERK') or (job not in('MANAGER','CLERK') and sal>=2000 )

4、找出早于25年之前受雇的雇员

SELECT * FROM EMP where (SYSDATE-HIREDATE)/365>25

5、显示所有雇员的姓名和加入公司的年份和月份，按雇员受雇日所在月排序，将最早年份的项目排最前面

select ename,to_char(hiredate,'yyyy'),to_char(hiredate,'MM') FROM EMP ORDER BY to_char(hiredate,'yyyy'),to_char(hiredate,'MM')   如果这么写 则按月份大小排序 select ename,to_char(hiredate,'yyyy'),to_char(hiredate,'MM') FROM EMP  ORDER BY to_char(hiredate,'MM'),to_char(hiredate,'yyyy')排序前后和orderby关系   第三种方法： select ename,to_char(hiredate,'yyyy'),to_char(hiredate,'MM') FROM EMP  ORDER BY  hiredate asc

6、以年、月和日显示所有雇员的服务年限

SELECT trunc((SYSDATE-HIREDATE)/365)||'年', trunc(mod((SYSDATE-HIREDATE),365)/30)||'月', trunc(mod(mod((SYSDATE-HIREDATE),365),30))||'日' FROM EMP   select trunc((sysdate-hiredate)/365) as Äê,  trunc(mod((sysdate-hiredate),365)/30) as ÔÂ,  trunc(mod(mod((sysdate-hiredate),365),30)) as ÈÕ  from emp

7、列出从事同一种工作但属于不同部门的雇员的

select * from emp t1,emp t2 where t1.job=t2.job and t1.deptno!=t2.deptno

8、列出分配有雇员数量的所有部门的详细信息，

select * from dept,( select deptno from emp group by deptno) t where dept.deptno=t.deptno

9列出每个部门的信息以及该部门中雇员的数量

select * from dept,( select deptno,count(*) num from emp group by deptno )t where dept.deptno=t.deptno

10列出至少有一个员工的所有部门

select * from dept,( select deptno from emp group by deptno) t where dept.deptno=t.deptno

11列出各个部门的MANAGER（经理）的最低薪金

select MIN(SAL) from emp where job='MANAGER' GROUP BY DEPTNO

12、复制emp表结构及数据(备分表名称为empback);

create table empback as select * from emp

13、创建一张与emp表结构一样的表（不需要emp表数据）、

create table empback as select * from emp where null=null

14、查询emp表中第31条到40条之间的数据（分页）

select * from ( select rownum n,t.* from (        select * from emp ) t where rownum <=20) where n>=10     select * from emp limit 30,10 为mysql数据库分页

15 已知表tabA结构如下，删除表tabA中属性t_name值重复的行 Create table  tabA(  t_id number, t_name varchar2(20) ) Insert into tabA (‘1’,’a); Insert into tabA (‘2’,’a); Insert into tabA (‘3’,’b); Insert into tabA (‘4’,’b); Insert into tabA (‘5’,’c);

delete from tabA where t_id not in( select min(t_id) from tabA group by t_name having count(*)>=2 ) and t_name in( select t_name from tabA group by t_name having count(*)>=2 )

16、显示雇员表中雇员的姓名，职务，薪水，部门表中的部门名称、地址以及工资等级表中的工资等级

select * from emp e,dept d,salgrade s where e.deptno=d.deptno and e.sal between losal and hisal