Oracle SQL Plan operation FIRST ROW

create table tq84_tab (
   id     integer      not null,
   txt    varchar2(10) not null,
   val    number(4,1)  not null,
   --
   constraint tq84_tab_pk primary key (id, txt)
);


insert into tq84_tab
select
   mod(level, 100),
   dbms_random.string('U', 2) || '.' || trunc((level-1)/100),
   dbms_random.value(1, 999)
from
   dual connect by level <= 10000;


begin
   dbms_stats.gather_table_stats(user, 'tq84_tab');
end;
/


explain plan for
select
   max(txt)
from
   tq84_tab
where
   id = 10
;
select * from table(dbms_xplan.display(format=>'basic'));
--
-- ----------------------------------------------------
-- | Id  | Operation                    | Name        |
-- ----------------------------------------------------
-- |   0 | SELECT STATEMENT             |             |
-- |   1 |  SORT AGGREGATE              |             |
-- |   2 |   FIRST ROW                  |             |
-- |   3 |    INDEX RANGE SCAN (MIN/MAX)| TQ84_TAB_PK |
-- ----------------------------------------------------


drop table tq84_tab;