Arredondar Valores

CREATE OR ALTER PROCEDURE PRO_ARREDONDAR_NOTA (ANOTA DOUBLE PRECISION)
RETURNS (RESULT DOUBLE PRECISION)
AS
  DECLARE VARIABLE DecPart DOUBLE PRECISION;
BEGIN
  RESULT = 0;

  DecPart = ROUND(ANOTA - TRUNC(ANOTA), 2) * 100;

  IF (DecPart = 50) THEN
    RESULT = ANOTA;
  ELSE
  IF (DecPart < 25) THEN
    RESULT = TRUNC(ANOTA);
  ELSE
  IF ((DecPart >= 25) AND (DecPart < 75))  THEN
    RESULT = TRUNC(ANOTA) + 0.5;
  ELSE
  IF (DecPart >= 75) THEN
    RESULT = TRUNC(ANOTA) + 1;

  SUSPEND;
END;