Questions fréquemment posées lors des entretiens avec Oracle

（1）查询20号部门的所有员工信息。
select * from emp where deptno = 20;
（2）查询所有工种为CLERK的员工的工号、员工名和部门名。
select empno,ename,deptno from emp where job like 'CLERK';
（3）查询奖金（COMM）高于工资（SAL）的员工信息。
select * from emp where comm > sal;
（4）查询奖金高于工资的20%的员工信息。
select * from emp where comm > (sal*0.2);
（5）查询10号部门中工种为MANAGER和20号部门中工种为CLERK的员工的信息。
select * from emp 
where (deptno = 10 and job like 'MANAGER') or (deptno = 20 and job like 'CLERK');
（6）查询所有工种不是MANAGER和CLERK，且工资大于或等于2000的员工的详细信息。
select * from emp 
where job not in ('MANAGER','CLERK') and sal >= 2000 ;
（7）查询有奖金的员工的不同工种。
select distinct job from emp where comm is not null;
（8）查询所有员工工资和奖金的和。
select ename,(sal+nvl(comm,0)) salcomm from emp;
（9）查询没有奖金或奖金低于100的员工信息。
select * from emp where (comm is null or comm < 100) ;
（10）查询各月倒数第2天入职的员工信息。
select * from emp where hiredate in (select (last_day(hiredate)-1) from emp);
（11）查询员工工龄大于或等于10年的员工信息。
select * from emp where (sysdate - hiredate)/365 >= 10 ;
（12）查询员工信息，要求以首字母大写的方式显示所有员工的姓名。
select upper(substr(ename,1,1)) || lower(substr(ename,2,length(ename)-1)) from emp;
（13）查询员工名正好为6个字符的员工的信息。
select * from emp where length（ename）= 6 ;
（14）查询员工名字中不包含字母“S”员工。
select * from emp where ename not in (select ename from emp where ename like &#39;%S%&#39;) ;
select * from emp where ename not like ‘%S%’;
（15）查询员工姓名的第2个字母为“M”的员工信息。
select * from emp where ename like &#39;_M%&#39;;
（16）查询所有员工姓名的前3个字符。
select substr(ename,1,3) from emp ;
（17）查询所有员工的姓名，如果包含字母“s”，则用“S”替换。
select replace(ename,&#39;s&#39;,&#39;S&#39;) from emp ;
（18）查询员工的姓名和入职日期，并按入职日期从先到后进行排列。
select ename,hiredate from emp order by hiredate asc ;
（19）显示所有的姓名、工种、工资和奖金，按工种降序排列，若工种相同则按工资升序排列。
select ename,job,sal,comm from emp order by job desc,sal asc ;
（20）显示所有员工的姓名、入职的年份和月份，若入职日期所在的月份排序，若月份相同则按入职的年份排序。
select ename,to_char(hiredate,&#39;yyyy&#39;)||&#39;-&#39;||to_char(hiredate,&#39;mm&#39;) from emp order by to_char(hiredate,&#39;mm&#39;),to_char(hiredate,&#39;yyyy&#39;);
（21）查询在2月份入职的所有员工信息。
select * from emp where to_char(hiredate,&#39;mm&#39;) = 2 ;
（22）查询所有员工入职以来的工作期限，用“**年**月**日”的形式表示。
select ename,floor((sysdate-hiredate)/365)||&#39;年&#39;||floor(mod((sysdate-hiredate),365)/30)||&#39;月&#39;||cell(mod(mod((sysdate-hiredate),365),30))||&#39;天&#39; from emp ;
（23）查询至少有一个员工的部门信息。
select * from dept where deptno in (select distinct deptno from emp where mgr is not null) ;
（24）查询工资比SMITH员工工资高的所有员工信息。
select * from emp where sal > (select sal from emp where ename like &#39;SMITH&#39;) ;
（25）查询所有员工的姓名及其直接上级的姓名。
select staname,ename supname from (select ename staname,mgr from emp) t join emp on t.mgr=emp.empno ;
（26）查询入职日期早于其直接上级领导的所有员工信息。
select * from emp where empno in (select staempno from (select empno staempno,hiredate stahiredate,mgr from emp) t join emp on t.mgr=emp.empno and stahiredate < hiredate) ;
（27）查询所有部门及其员工信息，包括那些没有员工的部门。
select * from dept left join emp on emp.deptno=dept.deptno order by dept.deptno ;
（28）查询所有员工及其部门信息，包括那些还不属于任何部门的员工。


（29）查询所有工种为CLERK的员工的姓名及其部门名称。
select ename,dname from emp join dept on job like &#39;CLERK&#39; and emp.deptno=dept.deptno ;
（30）查询最低工资大于2500的各种工作。
select job from (select min(sal) min_sal,job from emp group by job) where min_sal > 2500 ;
（31）查询最低工资低于2000的部门及其员工信息。
select * from emp where deptno in (select deptno from (select min(sal) min_sal,deptno from emp group by deptno) where min_sal < &#39;2000&#39;) ;
（32）查询在SALES部门工作的员工的姓名信息。
select ename from emp where deptno = (select deptno from dept where dname like &#39;SALES&#39;);
（33）查询工资高于公司平均工资的所有员工信息。
select * from emp where sal > (select avg(sal) from emp) ;
（34）查询与SMITH员工从事相同工作的所有员工信息。
select * from emp where job in (select job from emp where ename like &#39;SMITH&#39;) and ename not like &#39;SMITH&#39; ;
（35）列出工资等于30号部门中某个员工工资的所有员工的姓名和工资。
select ename,sal from emp where sal =any (select sal from emp where deptno = 30) ;
（36）查询工资高于30号部门中工作的所有员工的工资的员工姓名和工资。
select ename,sal from emp where sal >all (select sal from emp where deptno = 30) ;
（37）查询每个部门中的员工数量、平均工资和平均工作年限。
select dname,count,avg_sal,avg_date from dept join (select count(*) count,avg(sal) avg_sal,avg((sysdate-hiredate)/365) avg_date,deptno from emp group by deptno) t on dept.deptno = t.deptno ;
（38）查询从事同一种工作但不属于同一部门的员工信息。
select distinct t1.empno,t1.ename,t1.deptno from emp t1 join emp t2 on t1.job like t2.job and t1.deptno <> t2.deptno ;
（39）查询各个部门的详细信息以及部门人数、部门平均工资。
Select dept.*,person_num,avg_sal from dept,(select count(*) person_num,avg(sal) avg_sal,deptno from emp group by deptno) t where dept.deptno = t.deptno ;
（40）查询各种工作的最低工资。
select job,min(sal) from emp group by job ;
（41）查询各个部门中的不同工种的最高工资。
select max(sal),job,deptno from emp group by deptno,job order by deptno,job ；
（42）查询10号部门员工以及领导的信息。
select * from emp where empno in (select mgr from emp where deptno=10) or deptno = 10 ；
（43）查询各个部门的人数及平均工资。
select deptno,count(*),avg(sal) from emp group by deptno ；
（44）查询工资为某个部门平均工资的员工信息。
select * from emp where sal in (select avg(sal) avg_sal from emp group by deptno) ;
（45）查询工资高于本部门平均工资的员工的信息。
select emp.* from emp join (select deptno,avg(sal) avg_sal from emp group by deptno) t on emp.deptno=t.deptno and sal>avg_sal ;
（46）查询工资高于本部门平均工资的员工的信息及其部门的平均工资。
select emp.*,	 from emp join (select deptno,avg(sal) avg_sal from emp group by deptno) t on emp.deptno=t.deptno and sal>avg_sal ;
（47）查询工资高于20号部门某个员工工资的员工的信息。
select * from emp where sal >any(select sal from emp where deptno=20);
（48）统计各个工种的人数与平均工资。
select job,count(*),avg(sal) from emp group by job ;
（49）统计每个部门中各个工种的人数与平均工资。
select deptno,job,count(*),avg(sal) from emp group by deptno,job order by deptno,job;
（50）查询工资、奖金与10 号部门某个员工工资、奖金都相同的员工的信息。
select emp.* from emp join (select sal,comm from emp where deptno = 10) t on emp.sal=t.sal and nvl(emp.comm,0)=nvl(t.comm,0) and emp.deptno != 10;
（51）查询部门人数大于5的部门的员工的信息。
select * from emp where deptno in (select deptno from emp group by deptno having count(*)>5);
（52）查询所有员工工资都大于1000的部门的信息。
select * from dept where deptno in (select distinct deptno from emp where deptno not in (select distinct deptno from emp where sal < 1000)) ;
（53）查询所有员工工资都大于1000的部门的信息及其员工信息。
select * from emp join dept on dept.deptno in (select distinct deptno from emp where deptno not in (select distinct deptno from emp where sal < 1000)) and dept.deptno=emp.deptno;
（54）查询所有员工工资都在900~3000之间的部门的信息。
select * from dept where deptno in (select distinct deptno from emp where deptno not in (select distinct deptno from emp where sal not between 900 and 3000)) ;
（55）查询所有工资都在900~3000之间的员工所在部门的员工信息。
select * from emp where deptno in (select distinct deptno from emp where deptno not in (select distinct deptno from emp where sal not between 900 and 3000)) ;
（56）查询每个员工的领导所在部门的信息。
select * from (select e1.empno,e1.ename,e1.mgr mno,e2.ename mname,e2.deptno from emp e1 join emp e2 on e1.mgr=e2.empno) t join dept on t.deptno=dept.deptno ;
（57）查询人数最多的部门信息。
select * from dept where deptno in (select deptno from (select count(*) count,deptno from emp group by deptno) where count in (select max(count) from (select count(*) count,deptno from emp group by deptno)));
（58）查询30号部门中工资排序前3名的员工信息。
select * from emp where empno in (select empno from (select empno,sal from emp where deptno=30 order by sal desc) where rownum < 4) ;
（59）查询所有员工中工资排在5~10名之间的员工信息。
select * from emp where empno in (select empno from (select empno,rownum num from (select empno,sal from emp order by sal desc)) where num between 5 and 10 ) ;

select empno from (select empno,sal from emp order by sal desc) where rownum <= 10 minus select empno from (select empno,sal from emp order by sal desc) where rownum < 5 ;

（60）向emp表中插入一条记录，员工号为1357，员工名字为oracle，工资为2050元，部门号为20，入职日期为2002年5月10日。
insertinto emp(empno,ename,sal,deptno,hiredate) values (1357,&#39;oracle&#39;,2050,20,to_date(&#39;2002年5月10日&#39;,&#39;yyyy"年"mm"月"dd"日"&#39;)) ;
（61）向emp表中插入一条记录，员工名字为FAN，员工号为8000，其他信息与SMITH员工的信息相同。

（62）将各部门员工的工资修改为该员工所在部门平均工资加1000。
update emp t1 set sal = (select new_sal from (select avg(sal)+1000 new_sal,deptno from emp group by deptno) t2 wher e t1.deptno = t2.deptno ) ;
1、查询82年员工
select e.* from emp e where to_char(e.hiredate, &#39;yy&#39;) like &#39;82&#39;;
select e.* from emp e where to_char(e.hiredate,&#39;yyyy&#39;)=&#39;1982&#39;;
2、查询32年工龄的人员
 select round(sysdate-e.hiredate)/365, e.ename,e.hiredate from emp e where round((sysdate-e.hiredate)/365)=32;
3、显示员工雇佣期 6 个月后下一个星期一的日期
 select next_day(add_months(e.hiredate,6),2) from emp e ;
4、找没有上级的员工，把mgr的字段信息输出为 "boss"
 select decode(e.mgr,null,&#39;boss&#39;,&#39;中国好声音&#39;) from emp e;
5、为所有人长工资，标准是：10部门长10%；20部门长15%；30部门长20%其他部门长18%
  select decode(e.deptno,10,e.sal*1.1,20,e.sal*1.15, e.sal*1.18) 涨工资 ,e.deptno, e.sal from emp e ;
Oracle_练习与答案

1.求部门中薪水最高的人
 select ename,sal,emp.deptno from emp 
join (select deptno,max(sal) max_sal from emp group by deptno) t 
on (emp.deptno = t.deptno and emp.sal = t.max_sal); 

select ename, sal, deptno
 	from emp
where sal in (select max(sal) from emp group by deptno);
2.求部门平均薪水的等级
 select deptno, avg_sal, grade from 
(select deptno,avg(sal) avg_sal from emp group by deptno) t 
join salgrade 
on (t.avg_sal between salgrade.losal and salgrade.hisal);
3. 求部门平均的薪水等级 
select deptno, avg(grade) avg_sal_grade from (select deptno, grade from emp 
join salgrade on emp.sal between salgrade.losal and salgrade.hisal) group by deptno; 
4. 雇员中有哪些人是经理人 
select distinct e2.ename manager from emp e1 join emp e2 on e1.mgr = e2.empno; 
select ename from emp where empno in (select mgr from emp); 
5. 不准用组函数，求薪水的最高值 
  select distinct sal max_sal from emp where sal not in 
  (select e1.sal e1_sal from emp e1 join emp e2 on e1.sal < e2.sal);
select * from (select * from emp order by sal desc) t where rownum <2
6. 求平均薪水最高的部门的部门编号 
select deptno, avg_sal from (select deptno, avg(sal) avg_sal from emp group by deptno) 
where avg_sal =  (select max(avg_sal) from  (select avg(sal) avg_sal from emp group by
 deptno) );
组函数嵌套写法(对多可以嵌套一次，group by 只对内层函数有效) 
    select deptno, avg_sal from 
(select deptno, avg(sal) avg_sal from emp group by deptno) where avg_sal =  
(select max(avg(sal)) from emp group by deptno);
7. 求平均薪水最高的部门的部门名称 
select t1.deptno, dname, avg_sal from (select deptno,avg(sal) avg_sal from emp group by deptno) t1  join dept on t1.deptno = dept.deptno where avg_sal =  (select max(avg_sal) from  
(select deptno,avg(sal) avg_sal from emp group by deptno) ); 

select dname from dept where deptno =  (select deptno from 
(select deptno,avg(sal) avg_sal from emp group by deptno) where avg_sal =  
(select max(avg_sal) from  
(select deptno,avg(sal) avg_sal from emp group by deptno) ) ); 
8. 求平均薪水的等级最低的部门的部门名称 
select dname from dept join (select deptno, grade from 
(select deptno, avg(sal) avg_sal from emp group by deptno) t  join salgrade 
on (t.avg_sal between salgrade.losal and salgrade.hisal) ) t 
on dept.deptno = t.deptno where t.grade = (select min(grade) from 
(select avg(sal) avg_sal from emp group by deptno) t  join salgrade 
on (t.avg_sal between salgrade.losal and salgrade.hisal) ); 
 9.求部门经理人中平均薪水最低的部门名称
 select dname from  (select deptno, avg(sal) avg_sal from emp where empno in (select mgr from emp)group by deptno)t  join dept on t.deptno = dept.deptno where avg_sal = (select min(avg_sal) from (select avg(sal) avg_sal from emp where empno in 
(select mgr from emp) group by deptno) t ); 
10. 求比普通员工的最高薪水还要高的经理人名称(not in) 
select ename from emp where empno in (select mgr from emp) and sal > (select max(sal) from (select e2.sal from emp e1 right join emp e2 on e1.mgr = e2.empno where e1.ename is null) t ); 

select ename from emp where empno in (select mgr from emp) and sal > 
(select max(sal) from emp where empno not in (select distinct mgr from emp where mgr is not null) );
//NOT IN遇到NULL则返回NULL，必须排除NULL值
 11. 求薪水最高的前5名雇员 
select empno,ename from (select * from emp order by sal desc) where rownum<=5; 

12. 求薪水最高的第6到第10名雇(!important) 
select ename,sal from (select t.*,rownum r from  (select * from emp order by sal desc) t 
) where r>=6 and r<=10; 
13. 求最后入职的5名员工 
   select ename, to_char(hiredate,&#39;YYYY"年"MM"月"DD"日"&#39;) hiredate from (select t.*,rownum r from (select * from emp order by hiredate desc)t )
where r<=5; 

select ename, to_char(hiredate,&#39;YYYY"年"MM"月"DD""&#39;) hiredate from (select t.*,rownum r from  
(select * from emp order by hiredate)t 
)where r>(select count(*)-5 from emp);