I made an error during cut and paste while posting the SP- the output
parameter should be ID_OUT and is an integer type.
----
CREATE PROCEDURE P_TESTING (
DATE_IN TimeStamp)
returns (
ID_OUT Integer)
AS

begin
FOR SELECT PIM_APPOINTMENTS.APPOINTMENT_ID FROM PIM_APPOINTMENTS
WHERE
EXTRACT(MONTH FROM APPOINTMENT_STARTTIME) = EXTRACT(MONTH FROM :DATE_IN)
INTO
:ID_OUT
DO
SUSPEND;
end