DB: 서브쿼리(subquery) 사용 예제

* FROM 절 서브쿼리 (Top-N SQL)


--문hr> 입사순서 5명을 출력하라.(가장 오래된 사람)

SELECT employee_id, last_name, hire_date
    from employees
    order by hire_date ;

select rownum, alias.*
    from (SELECT employee_id, last_name, hire_date
        from employees
        order by hire_date )alias
  where rownum <= 5;

--퀴즈hr> 급여를 많이 받는순서 3명만 사원정보를 출력하라.
select * from emp00
order by salary desc;

select rownum, ades.*
--select rownum , ades.last_name, ades.employee_id,ades.email
  from (select * from emp00
        order by salary desc)ades
where rownum <= 3;