SQLD(SQL 개발자) 기출 · 집합 연산자

이 문제 풀어보기

1. 1.select *
   from (select job_id, max(salary) from
   Mytest
   group by salary
   union all
   select job_id, min(salary) from
   Mytest
   group by salary
   );
2. 2.select *
   from (select job_id, max(salary) from
   Mytest
   group by job_id
   union all
   select job_id, min(salary) from
   Mytest
   group by job_id
   );
3. 3.select *
   from (select job_id, max(salary) from
   Mytest
   group by salary
   union
   select job_id, min(salary) from
   Mytest
   group by salary
   );
4. 4.select *
   from (select job_id, max(salary) from
   Mytest
   group by job_id
   union
   select job_id, min(salary) from
   Mytest
   group by job_id
   );