Selecting FIRST record w/o fetching them all

Question

Hi:
Is there a way to select any one record from a set or potentially many without having to actually fetch them all?
For example, I want to get the last name of only one person with the first name 'joe' from the employees table. I don't care which "joe" it finds. I don't want Oracle to go through the expense of fetching them all before arbitrarily givnig me one of them.
select last_name from employees where first_name = 'joe' and rownum = 1;
...works, but I suspect that Oracle's getting all "joe"s before giving me the one where rownum=1.
I suppose I could do this with a cursor... open... fetch... close (only do 1 fetch), but is there a more elegant way?
Thanks in Advance!

Answer 1

I dunno about that.
I ran a query fetching a single record from a table which has close to 5 million records. I limited with "and rownum = 1". It took a long time, but eventually returned a valid answer.
I ran looking at the query plan, with and without the "rownum = 1". This is what I found...
SQL> explain plan set statement_id = 'foo' for select name from imp_insts where rownum = 1;
Explained.
SQL> select lpad(' ',2*LEVEL)||operation||' '||options||' '||object_name qplan
from plan_table
where statement_id='foo'
connect by prior id=parent_id and statement_id='foo'
start with id=1; 2 3 4 5
QPLAN
COUNT
FILTER
TABLE ACCESS FULL IMP_INSTS
SQL> delete from plan_table;
4 rows deleted.
SQL> explain plan set statement_id = 'foo' for select name from imp_insts;
Explained.
SQL>
select lpad(' ',2*LEVEL)||operation||' '||options||' '||object_name qplan
from plan_table
where statement_id='foo'
connect by prior id=parent_id and statement_id='foo'
start with id=1;SQL> 2 3 4 5
QPLAN
TABLE ACCESS FULL IMP_INSTS
SQL> select count(*) from imp_insts;
COUNT(*)
4936477
I see the "FILTER" but no "STOPKEY". I didn't trust the query that I used to show the execution plan, so I spooled "select * from plan_table" to a file and grep'd for both "STOP" and "KEY". No mention of STOPKEY.
Oracle8i on Tru64.