Hello FireBird Support!

I have this SQL statement in store procedure:

SELECT A.JEDIN,A.ROK,EXTRACT(YEAR FROM A.DATUM_VYSTAVENIA),A.DRUH_DOKLADU,
A.CISLO,A.DATUM_VYSTAVENIA,A.DATUM_UCTOVANIA,
A.DATUM_SPLATNOSTI,B.NAZOV_UPLNY,A.VARIABILNY_SYMBOL,A.UCTOVNY_UCET,
A.PRIJEM-A.VYDAJ,B.JEDIN,
(SELECT SUM(C.MA_DAT-C.DAL) FROM SALDOKONTO C WHERE
C.DATUM <= '2008/12/31' AND
C.PAROVACIE_CISLO = (SELECT FIRST 1 D.PAROVACIE_CISLO
FROM SALDOKONTO D
WHERE D.FAKTURY_JEDIN=A.JEDIN))
FROM FAKTURY A
LEFT JOIN ADRESAR B ON B.JEDIN=A.ADRESAR
WHERE A.DATUM_VYSTAVENIA<='2008/12/31' AND A.TYP_DOKLADU=4;

which has execution plan:

PLAN (D INDEX (FK_SALDOKONTO_FAKTURY))
PLAN (C INDEX (IDX_SALDOKONTO_PAROVACIE_CISLO, IDX_SALDOKONTO_DATUM))
PLAN JOIN (A INDEX (IDX_FAKTURY_DATUM_VYSTAVENIA), B INDEX (RDB$PRIMARY3))

where is no more natural selection, but the subselect gets it slow and
I have no more idea how to get it faster.

Any idea?

Many thanks in advance.

I'm using Firebird 2.1.

--
Best regards, TRoland
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