Best design for Boolean function from simple query

Question

Hello,
what is the most efficient, shorter, readable, simple way to make a boolean function that simply return true or false from a simple query that return 0 or 1 to n records?
Is this solution using a cursor's the best (working...):
   FUNCTION is_date_present (p_date IN DATE)
      RETURN BOOLEAN
   IS
      CURSOR chk_cursor
      IS
         SELECT COUNT (*)
           FROM target_dates
          WHERE target_date = p_date;
      nb   NUMBER := 0;
   BEGIN
      OPEN chk_cursor;
      FETCH chk_cursor
       INTO nb;
      CLOSE chk_cursor;
      IF nb >= 1
      THEN
         RETURN TRUE;
      ELSE
         RETURN FALSE;
      END IF;
   END;Performance, clarity and simplicity are important...
Thanks

Answer 1

Well, I prefer (not tested):
FUNCTION is_date_present (p_date IN DATE)
RETURN BOOLEAN
IS
nb NUMBER := 0;
BEGIN
SELECT COUNT (*)
INTO nb
FROM target_dates
WHERE target_date = p_date;
IF nb >= 1 THEN
RETURN TRUE;
LSE
RETURN FALSE;
IF;
END;Regards,
MiguelWhy count multiple records when you only care if you get at least 1 occurrence? Just wasted cycles.
FUNCTION is_date_present (p_date IN DATE)
RETURN BOOLEAN
IS
nb NUMBER := 0;
BEGIN
  SELECT COUNT (*)
  INTO nb
  FROM DUAL
  WHERE EXISTS
      SELECT NULL 
      FROM target_dates
      WHERE target_date = p_date
  IF nb >= 1 THEN
     RETURN TRUE;
  ELSE
     RETURN FALSE;
  END IF;
END;Or you could just add a ROWNUM = 1 on to yours, either way.