One can include the STAR_TRANSFORMATION hint. This requests that the optimizer select
the lowest cost plan after transforming the query. Without this hint the optimizer may choose the
lowest cost plan without first transforming the query. As mentioned, even if the query is
transformed by means of this hint, the optimizer may still decide that it is more efficient to use
an untransformed plan. But with this hint one can ensure that the transformed query is at least
SELECT /*+ STAR_TRANSFORMATION */
b.office_name, t.time_id, SUM(f.number_shares)
FROM transactions f, stocks s, brokerages b, time t
WHERE f.stock_id = s.stock_id
AND f.brokerage_id = b.brokerage_id
AND f.time_id = t.time_id
AND b.region = 'Central'
AND t.season = 'Spring'
AND s.industry = 'Banking'
GROUP BY b.office_name, t.time_id;