1：列出所有员工的姓名，部门名称，和工资
select a1.ename,a1.sal,a2.dname from emp a1,dept a2 where a1.deptno = a2.deptno;
2：列出所有部门的详细信息和部门人数
select a2.deptno,a2.dname,a2.loc,count(a1.empno) from emp a1,dept a2 where a1.deptno(+) = a2.deptno group by a2.deptno,a2.dname,a2.loc;
3：列出所有员工的年工资，所在部门名称，按年薪升序排列
select a1.sal*12 ,a2.dname from emp a1,dept a2 where a1.deptno = a2.deptno order by a1.sal*12;
4：查出每个员工的上级主管及所在部门名称，并要求这些主管的薪水超过3000
select employee.ename,boss.ename ,a1.dname from emp employee,emp boss,dept a1 where employee.mgr = boss.empno and boss.deptno = a1.deptno and boss.sal >3000;
5：求出部门名称中带’S’字符的部门员工的工资合计，部门人数
SELECT d.deptno,NVL(SUM(sal),0),COUNT(empno)FROM emp e,dept d WHERE e.deptno(+)=d.deptno AND d.dname LIKE '%S%' GROUP BY d.deptno ;
6：列出部门名称和这些部门的员工信息（数量，平均工资），同时列出那些没有员工的部门
select d.dname,avg(e.sal),count(e.empno) from emp e,dept d where e.deptno(+)=d.deptno group by d.dname;
7：列出在部门”SALES”工作的员工姓名，基本工资，雇用日期，部门名称，假定不知道销售部的部门编号
select a1.ename,a1.sal,a1.hiredate,a2.dname from emp a1,dept a2 where a1.deptno = a2.deptno and a2.dname = 'SALES';
8：列出公司各个工资等级雇员的数量，平均工资
select grade,count(*),avg(sal) from emp, salgrade where sal between losal and hisal group by grade;
9：列出薪水高于在部门30工作的所有员工的薪金的员工姓名和薪金，部门名称
select a1.ename,a1.sal,a2.dname from emp a1, dept a2 where a1.deptno = a2.deptno and sal > all(select sal from emp where deptno = 30);
10：列出受雇日期早于直接上级的所有员工的编号，姓名，部门名称，部门位置，部门人数
SELECT e.empno,e.ename,d.dname,d.loc,temp.count
FROM emp e,emp m,dept d,(
SELECT deptno dno, COUNT(empno) count
FROM emp
GROUP BY deptno) temp
WHERE e.mgr = m.empno(+) AND e.hiredate < m.hiredate
AND e.deptno = d.deptno
AND e.deptno = temp.dno;
11：列出所有“clerk”的姓名及其部门名称，部门人数，工资等级
SELECT e.ename , d.dname ,temp.count,s.grade
FROM emp e, dept d,(
SELECT deptno dno,COUNT(empno) count
FROM emp
GROUP BY deptno) temp,salgrade s
WHERE job='CLERK'
AND e.deptno = d.deptno
AND d.deptno = temp.dno
AND e.sal BETWEEN s.losal AND s.hisal;
12：列出最低薪金大于1500的各种工作及从事此工作的全部雇员人数及所在部门名称，位置，平均工资
SELECT t.job,t.count,d.dname,e.ename,reg.avg
FROM dept d,(
SELECT e.job,COUNT(e.empno) count
FROM emp e
GROUP BY e.job
HAVING MIN(e.sal)>1500
)t,emp e,(
SELECT deptno dno,AVG(sal) avg
FROM emp
GROUP BY deptno
)reg
WHERE e.deptno = d.deptno AND e.job = t.job
AND e.deptno = reg.dno;
13：列出薪金高于公司平均薪金的所有员工，所在部门，上级领导，公司的工资等级
select a1.ename,a2.dname,a1.mgr,a3.grade from emp a1,dept a2,salgrade a3,(select avg(sal) mysal from emp) a4 where a1.deptno = a2.deptno and sal between a3.losal and a3.hisal and a1.sal > a4.mysal;
14：列出与SCOTT从事相同工作的所有员工及部门名称，部门人数
SELECT e.empno,e.ename,e.job,d.dname,temp.count FROM emp e,dept d,(SELECT deptno dno,COUNT(empno) count FROM emp GROUP BY deptno) temp
WHERE e.job=(SELECT job FROM emp WHERE ename='SCOTT') AND e.ename<>'SCOTT' AND e.deptno=d.deptno AND temp.dno=e.deptno;
15：列出在每个部门工作的员工数量，平均工资，和平均服务年限
SELECT d.dname,count(e.empno),avg(e.sal),round(avg(sysdate-e.hiredate)/365) from emp e,dept d where e.deptno(+)=d.deptno GROUP BY d.dname;
16：列出各种工作的最低工资及此雇员姓名
select a1.ename,a1.job,a1.sal from emp a1,(select job,min(sal) min_sal from emp group by job) a2 where a1.job=a2.job and a1.sal=a2.min_sal;
17：列出各个部门的MANAGER的最低薪金，姓名，部门名称，部门人数
select e.sal,e.ename,d.dname, count from(select job,min(sal) sal,ename,deptno from emp where job='MANAGER'GROUP BY job,ename,deptno) e,
(select d.deptno,d.dname,count(e.empno) count fromemp e,dept d wheree.deptno=d.deptno GROUP BY d.deptno,d.dname) d
where e.deptno=d.deptno;
Oracle分页（根据ROWNUM分页）
select * from (select a1.*,rownum rn from (select ename,sal from emp order by sal) a1 where rownum<=10) where rn >=6;