Subquery Oracle

Funciones para subqueries
ver Documentación: aqui

Elemplos:

Select prod,year,sum(amt) from sales
group by rollup(prod,year);


WITH
DEPTOT AS (select sum(sal) as dsal from emp
group by deptno)
select avg(dsal) from deptot

- Subqueries recursivas
http://rwijk.blogspot.com/2009/11/recursive-subquery-factoring.html