CREATE FUNCTION GET_RACE_COUNT(OID integer, PID integer, STIME timestamp, 
				ETIME timestamp, RID integer) 
			RETURNS text AS
$BODY$
DECLARE
	K integer;
	Prev_Station integer;
	Time timestamp without timezone;
	Station integer;
	delta integer;
	SQLTEXT text;
BEGIN 
	FOR SELECT "Busdata"."Time", "Busdata"."Station" FROM "Busdata"
	WHERE ("Busdata"."Obj_ID" = OID) AND ("Busdata"."Proj_ID" = PID) 
	  AND ("Busdata"."Time" >= STIME) AND ("Busdata"."Time" <= ETIME)
	  AND ("Busdata"."Route" = RID)
        ORDER BY "Busdata"."Time"
        INTO Time, Station
        DO BEGIN
		IF (Station > Prev_Station) 
			THEN delta = Station - Prev_Station;
		ELSE
			delta = 0;
		K = K + delta;
		Prev_Station = Station;
	END
 
	SELECT COUNT(*) FROM "BusStation" WHERE "BusStation"."Route" = RID;
	RETURN "OK";
END
$BODY$