Oracle中面试题的查询语句

01． 查询员工表所有数据，并说明使用*的缺点



select * from emp;



01．查询职（job）为'PRESIDENT'的员工的工资



select sal from emp where job='PRESIDENT';



02．查询佣金为0或为null的员工的信息



select * from emp where comm is null or comm=1;



03．查询入职日期在1981-5-1到1981-12-31之间的所有员工的信息



select * from emp where hiredate between to_date(‘1-5月-81’) and to_date(‘31-12月-81’)



04．.查询所有名字长度为4的员工的员工的编号，姓名



select empno,ename from emp where length(ename)=4



05．显示10号部门饿所有经理和20号部门的所有员工



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



06．显示姓名没有'L'字的员工的详细信息或含有'SM'字的员工信息



select * from emp where ename not like '%L%' or ename like '%SM%';



07．显示各个部门经理的工资



select deptno,sal from emp where job='MANAGER';



08．显示佣金收入比工资高的员工的详细信息



select * from emp where comm>sal;







10．把hiredate列看做是员工的生日，求本月过生日的员工：



SQL> select * from emp



where to_char(hiredate,'mm')=to_char(sysdate,'mm');



11．把hiredate列看做是员工的生日，求下月过生日的员工



SQL> select * from emp



where to_char(hiredate,'mm')=to_char(add_months(sysdate,1



),'mm');



12.求1982年入职的员工



SQL> select * from emp where to_char(hiredate,'yyyy')='1982';



hiredate是date类型的，1982是字符串类型的，类型匹配才可以



13．求1981年下半年入职的员工



select * from emp



where hiredate between to_date('1981-7-1','yyyy-mm-dd')



and to_date('1982-1-1','yyyy-mm-dd')-1;



注：to_char()函数和to_date()函数



to_char()函数是把日期的类型转换为指定的格式



to_date()是把字符串转换为日期类型



-1的原因是更精确



14．求1981年各个月入职的员工个数



SQL> select to_char(hiredate,'mm'),count(*) from emp where to_char(hiredate,'yyy



y')='1981' group by to_char(hiredate,'mm') order by to_char(hiredate,'mm');







或



select to_char(hiredate,'mm'),count(*) from emp where to_char(hiredate,'yyyy')='1981' group by to_char(hiredate,'mm') order by to_char(hiredate,'mm');







PartII



01 .查询各个部门的平均工资



SQL> select deptno,avg(nvl(sal,0)) from emp group by deptno;



02.显示各种职位的最低工资



SQL> select job,min(sal) from emp group by job;



03．按照入职日期由新到旧排列员工信息



SQL> select hiredate from emp order by hiredate desc;



04．查询员工的基本信息，附加其上级的姓名（自关联）



SQL> select e.*,e1.ename from emp e,emp e1 where e.mgr=e1.empno;



05．显示工资比’ALLEN’高的所有员工的姓名和工作



SQL> select ename,sal from emp where sal>(



select sal from emp where ename='ALLEN');



06．显示与scott从事相同工作的员工的信息（子查询）



SQL> select * from emp where job=(



select job from emp where ename='SCOTT');



07．显示销售部(‘SALES’)员工的姓名



SQL> select e.ename from emp e inner join dept d on e.deptno=d.deptno where d.dname='SALES';



08．显示与30号门’MARTIN’员工工资相同的员工的姓名和工资



SQL> select ename,sal from emp where sal=(select sal from emp where deptno=30 and ename='MARTIN');



09．查询所有工资高于平均工资（包括所有员工）的销售人员



SQL> select * from emp where sal>(



select avg(sal) from emp) and job='SALESMAN';



或



SQL> select * from emp where job='SALESMAN' and sal>(



select avg(sal) from emp);



10．显示所有职员的姓名及其所在部门的名称和工资(表连接)



SQL> select e.*,e.sal,d.dname from emp e inner join dept d on e.deptno=d.deptno;



11．查询在研发部(RESEARCH)工作人员的编号，姓名，工作部门，工作所在地



SQL> select e.empno,e.ename,d.dname,d.loc from emp e inner join dept d on e.deptno=d.deptno where dname='RESEARCH';



12．查询各个部门的名称和员工人数



select e.deptno,d.dname,count(*) from emp e inner join dept d on e.deptno=d.deptno group by e.deptno,d.dname







分析：



SQL> select d.dname from emp e inner join dept d on e.deptno=d.deptno group by e.deptno,d.dname;







DNAME



--------------



ACCOUNTING



RESEARCH



SALES







SQL> select e.deptno,d.dname from emp e inner join dept d on e.deptno=d.deptno group by e.deptno,d.dname;







DEPTNO DNAME



------ --------------



10 ACCOUNTING



20 RESEARCH



30 SALES







SQL> select e.deptno,d.dname,count(*) from emp e inner join dept d on e.deptno=d.deptno group by e.deptno,d.dname;







DEPTNO DNAME COUNT(*)



------ -------------- ----------



10 ACCOUNTING 3



20 RESEARCH 5



30 SALES 6











13．查询各个部门员工工资大于平均工资（平均工资包括所有员工）的人数和员工职位(子查询)







SQL> select count(*),job from emp where sal>(select avg(sal) from emp) group by job;



14．查询工资相同的员工的工资和姓名（子查询）



SQL> select sal,ename from emp e where(select count(*) from emp where sal=e.sal group by sal)>1;



或



SQL> select e.sal,e.ename from emp e,emp e1 where e.sal=e1.sal and e.ename<>e1.ename;



15．查询工资最高的3名员工信息(排序)



SQL> select rownum,e1.* from (



select e.* from emp e order by sal desc) e1



where rownum<=3;



rownum是伪列，记性排序的



16．按工资进行排名：排名从1开始，工资相同排名相同（如果两个并列第1则没有地2名，从第三名继续排）



SQL> select e.*,(select count(*) from emp where sal>e.sal)+1 rank from emp e order by rank;



或 select sal,rank() over(order by sal desc) from emp;



17．求入职日期相同的（年月日相同）的员工



SQL> select * from emp e where(select count(*) from emp where e.hiredate=hiredate)>1;



或



SQL> select * from emp e,emp e1 where e.hiredate=e1.hiredate and e.empno<>e1.empno;







18．查询每个部门的最高工资



SQL> select max(sal),deptno from emp group by deptno order by deptno;



19．查询每个部门，每个职位的最高工资



SQL> select deptno,job,max(sal) from emp group by deptno,job　order by deptno;



20．查询每个员工的信息及工资级别，用到表(Salgrade)



SQL> select e.ename,s.grade from emp e,salgrade s where sal between losal and hisal;



或



select e.*,s.grade from emp e inner join salgrade s on e.sal between s.losal and s.hisal



21.查询工资最高的第6-10名员工



SQL> select * from (select rownum as r,e.* from (select * from emp order by sal desc) e) e1 where e1.r>=6 and e1.r<=10;



或



SQL> select * from(



select rownum as r,e.* from emp e order by sal desc) e1



where e1.r>=6 and e1.r<=10;



或



select * from (select rownum r,e1.* from (select e.* from emp e order by sal desc) e1 where rownum<10) e2 where e2.r>=6







结果：



R SAL



---------- -----



6 2450



7 1600



8 1500



9 1300



10 1250







Order by不能和rownum合用，











可以做分页啦！！



22．查询各个部门工资最高的员工信息



SQL> select * from emp e where e.sal=(



select max(sal) from emp where (deptno=e.deptno));



或



select * from emp e,(select deptno,max(sal) maxSal from emp group by deptno) e1 where e.sal=maxSal and e.deptno=e1.deptno



或



select * from emp e inner join (select deptno,max(sal) maxSal from emp group by deptno) e1 on e.sal=maxSal and e.deptno=e1.deptno







23．查询每个部门工资最高的前2名员工



SQL> select * from emp e where (



select count(*) from emp where sal>e.sal and e.deptno=deptno)<2



order by deptno,sal desc;







24．查询出有3个以上下属的员工信息（自关联）



select * from emp e where (



select count(*) from emp where e.empno=mgr)>2



25．查询所有大于本部平均工资的员工信息



SQL> select * from emp e where sal>(



select avg(sal) from emp where e.deptno=deptno);



或



select * from emp e,(select deptno,avg(sal) avgSal from emp group by deptno) e1 where e.sal>avgSal and e.deptno=e1.deptno;



26．查询平均工资最高的部门信息



select d.* from dept d,(select deptno,avg(sal) av from emp group by deptno) where av=(select max(avg(sal)) from emp group by deptno) and e.deptno=d.deptno







或



select d.* from dept d where deptno=(select e.deptno from (select max(avgSal) maxSal from (select deptno,avg(nvl(sal,0)) avgSal from emp group by deptno)) e1 inner join (select deptno,avg(nvl(sal,0)) avgSal from emp group by deptno) e on e.avgSal=e1.maxSal)







注：如果在当前行的字段在查询的时候不能用别名：



select dname,deptno dp from dept where dp=10







ORA-00904: "DP": 标识符无效



SQL> select dname,deptno dp from dept where deptno=10;







DNAME DP



-------------- ---



ACCOUNTING 10







也不能使用在inner join on条件中，可以使用在order by中，



别名放在from子句（select 。。。。别名 使用from）之后，这个别名可以在任何位置







在having中也不能使用别名











27．查询大于各个部门总工资的平均值的部门信息



select d.*,sumsal from dept d,(select sum(nvl(sal,0)) sumsal,deptno from emp group by deptno) sumS where sumSal>(select avg(sum(nvl(sal,0))) from emp group by deptno) and sumS.deptno=d.deptno







28．查询大于各个部门总工资平均值的部门下的员工信息



select e.* from emp e,(select sum(nvl(sal,0)) sumSal,deptno from emp group by deptno) e1 where



sumSal>(select avg(sum(nvl(sal,0))) from emp group by deptno) and e1.deptno=e.deptno



29．查询么有员工的部门信息



select * from dept where deptno not in(select deptno from emp group by deptno);