Oracle数据库查询的使用实例记录

Oracle数据库使用实例记录

显示所有在欧洲区域工作的员工，显示他们的部门，姓名，岗位，薪资，国籍，结果按照国籍升序，薪资降序排列              select d.department_name, e.last_name, e.job_id, e.salary, c.country_name 
from employees e, departments d, locations l, regions r, countries c 
where e.department_id = d.department_id 
and d.location_id = l.location_id 
and l.country_id = c.country_id 
and c.region_id = r.region_id 
and r.region_name = 'Europe' 
order by country_name, salary desc;
用尽可能多的方式显示姓名以小写’s’结尾的人员总数；至少2种方法
第一种方法                                                                                                                                                                           select count(*) from employees 
where last_name like '%s';

第二种方法
select count(*) from employees 
where substr(last_name,-1)='s';                                                                                                                                                                                                                                                                                                                                                       正则表达式                                                                                                                                                                                select count(*)
from employees
where regexp_like(last_name,'(*)s$');

查询所有薪资大于‘IT_PROG’部门任何一人的薪资员工信息，显示姓名、薪资、岗位；用2种方法实现                                  第一种方法                                                                                                                                                                        select employee_id,first_name,last_name,salary,job_id 
from employees 
where salary > any(select salary from employees where job_id='IT_PROG') 
order by salary;                                                                                                                                                                      第二种方法                                                                                                                                                                          select employee_id,first_name,last_name,salary,job_id
from employees
where salary > (select min(salary)
                  from employees
                  where job_id='IT_PROG')
order by salary; 
创建一张表与employees表相同的表，表名：employees_工号;将’Marketing’，’IT’ 两个部门下员工导入该表。提供脚本
create table employees_工号 as select * from employees where 1=2;

insert into employees_工号 (select * from employees 
where job_id like 'IT%' or job_id like 'MK%');

查询HR下所有的约束/索引                                                                                                                                                   select index_name ,index_type FROM dba_indexes WHERE owner='HR';