There may be cases where more than one plan fragment is needed. For example, you might want to specify that some index should be used for each table in the query, but leave the join order up to the optimizer. When multiple hints are needed, they can be grouped with the hints operator:
(hints
(i_scan () t1)
(i_scan () t2)
(i_scan () t3)
)
In this case, the role of the hints operator is purely syntactic; it does not affect the ordering of the scans.
There are no limits on what may be given as a hint. Partial join orders may be mixed with partial access methods. This hint specifies that t2 is outer to t1 in the join order, and that the scan of t3 should use an index, but the optimizer can choose the index for t3, the access methods for t1 and t2, and the placement of t3 in the join order:
(hints
(g_join
(scan t2)
(scan t1)
)
(i_scan () t3)
)
