Checking for existence [newbie]

I have to find out the existence of tasks for an employee, and for a time period.

Now I do

SELECT COUNT(*)
FROM TASKS
WHERE EMPNO = 239 AND
    TASK_DATE >= SYSDATE-4 AND
    TASK_DATE <= SYSDATE-1;

If COUNT(*) gives value greater than 0,
then I know that that employee had some tasks in the given time period. However is there a better trick? Function COUNT(*) is too slow and I have to find just ONE row. Received on Thu May 15 2003 - 17:27:52 CDT