查找部门30中员工的详细信息：

select * from emp where deptno = 30;

找出从事CLERK工作的员工编号、姓名、部门号：

select empno, ename, deptno from emp where job = 'CLERK';

检索奖金多于基本工资的员工信息：

select * from emp where comm > sal;

检索奖金多于基本工资60%的员工信息：

select * from emp where comm > sal * 0.6;

找出10部门的经理和20部门的职员的员工信息：

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

找出10部门的经理、20部门的职员或工资高于2000元的员工信息：

select * from emp where (deptno = 10 and job = 'MANAGER') or (deptno = 20 and job = 'CLERK') or (sal > 2000);

找出获得奖金的员工的工作：

select * from emp where comm is not null;

找出奖金少于100或没有获得奖金的员工信息：

select * from emp where comm < 100 or comm is null;

找出名字以A、B、S开始的员工信息：

select * from emp where ename like 'A%' or ename like 'B%' or ename like 'S%';

找出名字长度为7个字符的员工信息：

select * from emp where length(ename) = 7;

找出名字中不包含R字符的员工信息：

select * from emp where ename not like '%R%';

查询所有姓李的员工英语成绩：

select name, english from emp where name like '李%';

查询数学分数大于80并且语文分数大于80的员工信息：

select * from emp where math > 80 and chinese > 80;

查询英语成绩大于80或总分大于200的员工信息：

select * from emp where english > 80 or (chinese + math + english) > 200;

按数学成绩排序输出：

select * from emp order by math;

按总分排序输出，按从高到低的顺序：

select * from emp order by (chinese + math + english) desc;

查询姓名为'李一'的学生成绩：

select name, chinese, math, english from emp where name = '李一';

查询英语成绩大于90分的同学：

select name from emp where english > 90;

查询总分大于200分的所有同学：

select name from emp where (chinese + math + english) > 200;

查询英语分数在80－90之间的同学：

select name from emp where english >= 80 and english <= 90;

查询数学分数为89,90,91的同学：

select name from emp where math in (89, 90, 91);

查询所有姓李的学生英语成绩：

select name, english from emp where name like '李%';

查询数学分数大于80并且语文分数大于80的同学：

select name from emp where math > 80 and chinese > 80;

查询英语成绩大于80或者总分大于200的同学：

select name from emp where english > 80 or (chinese + math + english) > 200;

按总分排序后输出，按从高到低的顺序：

select name, (chinese + math + english) as Total from emp order by Total desc;

查询总分大于200的同学，并按总分排序：

select name, (chinese + math + english) as Total from emp where Total > 200 order by Total desc;

查询英语成绩大于80或总分大于200的同学：

select name from emp where english > 80 or (chinese + math + english) > 200;

按数学成绩排序后输出：

select * from emp order by math desc;

查询部门号、部门名、部门所在位置及其每个部门的员工总数：

select deptno, dname, loc, count(*) from emp ee, dept dd where ee.deptno = dd.deptno;

返回员工的姓名、所在部门名及其工资：

select ee.ename, dd.dname, ee.sal from emp ee, dept dd where ee.deptno = dd.deptno;

返回员工的详细信息：

select * from emp, dept, salgrade where dept.deptno = emp.deptno;

返回工资水平多于smith的员工信息：

select * from emp where sal > (select sal from emp where ename = 'smith');

返回与SCOTT从事相同工作的员工：

select * from emp where job = (select job from emp where ename = 'SCOTT') and ename != 'SCOTT';

返回工资高于30部门所有员工工资水平的员工信息：

select * from emp where sal > (select max(sal) from emp where deptno = 30);

返回工资为二等级的职员名字、部门所在地、二等级员工工资的最低工资和最高工资：

select ename, loc, losal, hisal from emp, salgrade where grade = 2 and sal between losal and hisal;

返回工资处于第四级别的员工姓名：

select ename from emp, salgrade where grade = 4 and sal between losal and hisal;

返回工资为二等级的职员名字、部门所在地、二等级员工工资的最低工资和最高工资：

select ename, loc, (select min(sal) from emp, salgrade where grade = 2 and sal between losal and hisal), (select max(sal) from emp, salgrade where grade = 2 and sal between losal and hisal) from emp, salgrade, dept where emp.deptno = dept.deptno and grade = 2;

返回工资为二等级的职员名字、部门所在地、二等级员工工资的最低工资和最高工资：

select ename, loc, (select min(sal) from emp, salgrade where grade = 2 and sal between losal and hisal), (select max(sal) from emp, salgrade where grade = 2 and sal between losal and hisal) from emp, dept where emp.deptno = dept.deptno and grade = 2;

返回工资为二等级的职员名字、部门所在地、二等级员工工资的最低工资和最高工资：

select ename, loc, (select min(sal) from emp, salgrade where grade = 2 and sal between losal and hisal), (select max(sal) from emp, salgrade where grade = 2 and sal between losal and hisal) from emp, dept where emp.deptno = dept.deptno and grade = 2;

返回工资高于30部门所有员工工资水平的员工信息：

select * from emp where sal > (select avg(sal) from emp where deptno = 30);