%%How to <efficiently> do: SELECT MAX(Date)...WHERE Date < myParamDate

Say I have a "rating history" table like this:

RATING     RDATE
-----------       ---------
   5             01-JAN-97
   4             01-FEB-97
   3             01-MAR-97

If i want to determine what the rating was at 2/15/97 (it was updated to 4 on 2/1/97) I can do the following:

select rating from rating_tbl where rdate =
(select max(rdate)

from rating_tbl
where rdate < to_date('2/15/97','MM-DD-YYYY'));

Can I be more efficient & do this w/o a subselect?

insert into rating values (1, 5 ,to_date('1/1/97','MM-DD-YYYY'));
insert into rating values (1, 4 ,to_date('2/1/97','MM-DD-YYYY'));
insert into rating values (1, 3 ,to_date('3/1/97','MM-DD-YYYY'));
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