Oracle根据数据字典的查询练习

根据数据字典，查询当前用户下有哪些表 select * from all_tables t where t.owner ='hr'; 查询所有员工编号，员工姓名、邮件、雇佣日期、部门、部门详细地址信息 select e.employee_id,e.first_name||e.last_name as full_name, e.email,e.hire_date,

d.department_name,m.first_name||m.last_name as manager_name,

street_address,city,state_province

from employees e,employees m,departments d,locations l

where e.manager_id=m.employee_id

and e.department_id=d.department_id

and d.location_id=l.location_id; 查询1997年入职员工员工编号，员工姓名，雇佣日期，工龄(保留2位小数)、按照first_name升序排列

select employee_id,first_name,last_name,round((sysdate-hire_date)/365,2) as work_age

from employees

where to_char(hire_date,'yyyy') = 1997

order by first_name

显示姓、薪水，佣金(commission) ，然后按薪水降序排列

select first_name,last_name,salary,commission_pct

from employees

order by salary desc

显示姓名、薪水，佣金，佣金为空的，统一加上0.05;其余的加上0.03，按照薪资降序、变更后佣金升序排列

select first_name,last_name,salary,commission_pct, nvl2(commission_pct,commission_pct+0.03,0.05) new_commission_pct

from employees

order by new_commission_pct asc , salary desc 显示名字以j、k、l、m开头的雇员

select *

from employees

where substr(first_name,1,1) in ('j','k','l','m') or substr(last_name,1,1) in ('j','k','l','m')

显示员工姓名，薪水，调整后薪水(按部门调整：it提升30%,salse 提升50%、其余部门提升20%);按照调整后薪水升序排列

select first_name,last_name,salary,department_name,

case department_name

when 'it' then 1.30*salary

when 'sales' then 1.50*salary

else 1.20*salary

end "revised_salary"

from employees left join departments on

employees.department_id = departments.department_id

order by revised_salary

显示在每月中旬雇佣的员工,显示姓名，雇佣日期

select first_name,last_name,hire_date

from employees

where to_char(hire_date, 'dd') between 11 and 20