1.查询工资大于12000的员工姓名和工资Select last_name||' '||first_name,salary from employees where salary >12000;2.查询员工号为176的员工的姓名和部门号Select last_name||' '||first_name,department_id from employees where employee_id=176;3.选择工资不在5000到12000的员工的姓名和工资Select last_name||' '||first_name,salary from employees where salary not between 5000 and 12000;4.选择雇用时间在1998-02-01到1998-05-01之间的员工姓名，job_id和雇用时间Select last_name||' '||first_name,job_id,hire_date from employees where hire_date between '1-2月-98' and '1-5月-98';5.选择在20或50号部门工作的员工姓名和部门号Select last_name||' '||first_name,department_id from employees where department_id in (20,50);6.选择在1994年雇用的员工的姓名和雇用时间Select last_name||' '||first_name,hire_date from employees where hire_date like '%94';7.选择公司中没有管理者的员工姓名及job_idSelect last_name||' '||first_name,job_id from employees where Manger_id is null;8.选择公司中有奖金的员工姓名，工资和奖金Select last_name||' '||first_name,salary,commission_pct from employees where commission_pct is not null;9.选择员工姓名的第三个字母是a的员工姓名Select last_name||' '||first_name from employees where last_name||' '||first_name like '___a%';10.选择姓名中有字母a和e的员工姓名Select last_name||' '||first_name from employees where last_name||first_name like '%a%e%' or last_name||first_name like '%e%a%';多表查询11.显示所有员工的姓名，部门号和部门名称。

Select st_name,d.department_id,d.department_name from employeese , departments d where (e.department_id=d.department_id);12.查询90号部门员工的job_id和90号部门的location_idSelect e.job_id,d.location_id from employees e, departments d wheree.department_id=d.deparement_id and d.department_id=90;13.选择所有有奖金的员工的last_name , department_name , location_id , citySelect st_name , d.department_name , l.location_id , city from employees e,departments d,locations l where e.department_id=d.department_id AND d.location_id=l.location_idAND commission_pct is not null;14.选择在Toronto工作的员工的last_name , job_id , department_id , department_nameSelect st_name , e.job_id , d.department_id , d.department_name from employees e,departments d ,locations l where e.department_id=d.department_id AND d.location_id=l.location_id AND l.city='Toronto';15.选择所有员工的姓名，员工号，以及他的管理者的姓名和员工号，结果类似于下面的格式Select e.employee_id "employees",st_name "Emp#",d.manager_id "Mgr#",st_name "manger" from employees e,employees d wheree.manager_id=d.employee_id(+);6. 查询各部门员工姓名和他们的同事姓名，结果类似于下面的格式Select e.department_id "Department_id", st_name "Last_name", st_name "colleague" from employees e join employees d on(d.department_id=e.department_id) where st_name<>st_name;分组查询16.组函数处理多行返回一行（true）17.组函数不计算空值（false）18.where子句在分组之前对检索进行过滤( true)19.查询公司员工工资的最大值，最小值，平均值，总和Select max(salary),min(salary),avg(salary),sum(salary) from employees;20.查询各job_id的员工工资的最大值，最小值，平均值，总和Select max(salary),min(salary),avg(salary),sum(salary) from employees group by job_id;21.选择具有各个job_id的员工人数Select job_id,count(*) from employees group by job_id;22.查询员工最高工资和最低工资的差距（DIFFERENCE）Select max(salary)-min(salary) "DIFFERENCE" from employees;23.查询各个管理者手下员工的最低工资，其中最低工资不能低于6000，没有管理者的员工不计算在内Select manager_id,min(salary) from employees where manager_id is not null group by manager_id having min(salary) >=6000;24.查询所有部门的名字，location_id，员工数量和工资平均值Selectd.department_name,d.location_id,count(e.employee_id),avg(e.salary) from employees e,departments d where e.department_id(+)=d.department_id group byd.location_id,d.department_name;25.查询公司的人数，以及在1995-1998年之间，每年雇用的人数，结果类似下面的格式Select count(employee_id),to_char(hire_date,'yyyy') "y";count(*) from employees where to_char(hire_date,'yyyy') between 1995 and 1998 group by to_char(hire_date,'yyyy') order by y;Select子查询26.查询和zlotkey相同部门的员工姓名和雇用日期Select last_name,hire_date,department_id from employees where department_id=(select department_id from employees where lower(last_name)='zlotkey') ;27.查询工资比公司平均工资高的员工的员工号，姓名和工资。

Select employee_id,last_name,salary from employees where salary>(select avg(salary) from employees );28.查询和姓名中包含字母u的员工在相同部门的员工的员工号和姓名Select employee_id,last_name,department_id from employees where department_id =any (select department_id from employees where lower(last_name) like '%u%');29.查询在部门的location_id为1700的部门工作的员工的员工号，department_id和job_idSelect employee_id,department_id,job_id from employees where department_id = any (select department_id from departments where location_id=1700);30.查询管理者是king的员工姓名和工资Select last_name,salary from employees where manager_id=(select employee_id from employees where last_name='King');创建和管理表31.创建表deptCreate table dept( id Number(7),name varchar(25));32.将表departments中的数据插入表dept中Insert into dept(SELECT department_id, department_nameFROM departments);33.创建表empCreate table emp (id Number(7),First_name varchar(25),Last_name varchar(25),Dept_id number(7));34.将列Last_name的长度增加到50Alter table emp modify (last_name varchar2(50));35.查询数据字典视图user_tables检查刚才的操作Select * from user_tables;36.根据表employees创建employees2Create table employees2 asselect * from employees;37.删除表empDrop table emp;38.将表employees2重命名为empRename employees2 to emp;39.在表dept和emp中添加新列test_column，并检查所作的操作Alter table emp add(test_column varchar(10));单行函数40.显示系统时间Select to_char(sysdate 'DD-MON-YYYY')from dual;41.查询员工号，姓名，工资，以及工资提高百分之20%后的结果（newsalary）Select employee_id,last_name||' '||first_name,salary,salary*1.2 newsalary from employees;42.将员工的姓名按首字母排序，并写出姓名的长度（length）Select last_name,length(last_name) from employees order by substr(last_name,1,1) desc;43.查询各员工的姓名，并显示出各员工在公司工作的月份数（worked_month）。