why oh why procedure

Hi all....
I want to create store procedure and the sql is

CREATE PROCEDURE CARI_DATA
(NIM VARCHAR(10),
TAHUNAJARAN VARCHAR(4),
KD_MSUJI VARCHAR(2),
BEBAN SMALLINT,
JENJANG VARCHAR(3))
RETURNS (
KDMK_JUR VARCHAR(12),
NM_MKULIAH VARCHAR(25),
SKS SMALLINT,
BAYAR DOUBLE PRECISION,
KELAS VARCHAR(2),
JENJANG VARCHAR(3))
AS
BEGIN
SELECT T_MATAKULIAH.KDMK_JUR,
T_MATAKULIAH.NM_MKULIAH,
T_MATAKULIAH.SKS,
(CAST(T_MATAKULIAH.TARIP AS DOUBLE PRECISION)) AS bayar,
KRS_.KELAS,
UANG_SKS.JENJANG
FROM T_MATAKULIAH INNER JOIN (T_MAHASISWA INNER JOIN KRS_ ON
T_MAHASISWA.NIM = KRS_.NIM) ON T_MATAKULIAH.KDMK_PUS = KRS_.KDMK_PUS
INNER JOIN UANG_SKS ON T_MAHASISWA.ANGKATAN = UANG_SKS.ANGKATAN
WHERE
(((KRS_.NIM)= :nim) AND
((KRS_.TAHUNAJARAN)= :tahunajaran)AND
((KRS_.KD_MSUJI)= :kd_msuji) AND
((T_MATAKULIAH.BEBAN)= :beban)) and
((uang_sks.jenjang)= :jenjang)
into :KDMK_JUR, :NM_MKULIAH, :SKS, :BAYAR, :KELAS, :JENJANG
union
SELECT T_MATAKULIAH.KDMK_JUR, T_MATAKULIAH.NM_MKULIAH, T_MATAKULIAH.SKS,
(CAST(SKS*UANGSKS*BEBAN/100 AS DOUBLE PRECISION)) AS bayar,
KRS_.KELAS,
uang_sks.jenjang
FROM T_MATAKULIAH INNER JOIN ((UANG_SKS INNER JOIN T_MAHASISWA ON
UANG_SKS.ANGKATAN = T_MAHASISWA.ANGKATAN) INNER JOIN KRS_ ON
T_MAHASISWA.NIM = KRS_.NIM) ON T_MATAKULIAH.KDMK_PUS = KRS_.KDMK_PUS
WHERE (((KRS_.NIM)= :nim) AND ((KRS_.TAHUNAJARAN)= :tahunajaran)
AND ((KRS_.KD_MSUJI)= :kd_msuji) AND (T_MATAKULIAH.BEBAN) <> :beban) and
((uang_sks.jenjang)= :jenjang)
into :KDMK_JUR, :NM_MKULIAH, :SKS, :BAYAR, :KELAS, :JENJANG
union
SELECT T_MKKHUSUS.KDMK_JUR, T_MKKHUSUS.NM_MKULIAH,T_MKKHUSUS.SKS,
(CAST(BEBANBAYAR*UANGSKS AS DOUBLE PRECISION)) AS bayar, KRS_.KELAS,
UANG_SKS.JENJANG
FROM (T_MATAKULIAH INNER JOIN ((UANG_SKS INNER JOIN T_MAHASISWA ON
UANG_SKS.ANGKATAN = T_MAHASISWA.ANGKATAN) INNER JOIN KRS_ ON
T_MAHASISWA.NIM = KRS_.NIM) ON T_MATAKULIAH.KDMK_PUS = KRS_.KDMK_PUS)
INNER JOIN T_MKKHUSUS ON T_MATAKULIAH.KDMK_PUS = T_MKKHUSUS.KDMK_PUS
WHERE (((KRS_.NIM)= :nim) AND ((KRS_.TAHUNAJARAN)= :tahunajaran)
AND ((KRS_.KD_MSUJI)= :kd_msuji)) and ((uang_sks.jenjang)= :jenjang)
into :KDMK_JUR, :NM_MKULIAH, :SKS, :BAYAR, :KELAS, :JENJANG;
EXIT;
END;

but every time i run it the error message is that union cannot be execute.
is store procedure do not support union??

Thank you
Dedy Styawan

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