14일차 # 4-14: grouping sets를 이용하여 rollup, cube 구현

 1) rollup

  select deptno, job, sum(sal) as sum_sal

  from emp

  group by rollup(deptno, job)

  order by 1, 2;

↓ ↓ ↓

  select deptno, job, sum(sal) as sum_sal

  from emp

  group by grouping sets((deptno, job), (deptno), ())

  order by 1, 2;

  2) cube

  select deptno, job, sum(sal) as sum_sal

  from emp

  group by cube(deptno, job)

  order by 1, 2;

↓ ↓ ↓

  select deptno, job, sum(sal) as sum_sal

  from emp

  group by grouping sets((deptno, job), (deptno), job, ())

  order by 1, 2;