Hi all,

I have a problem with indexes in my firebird query.

Below is my query.

select a.objid, b.running_qty, b.running_qty2, b.running_totalcost, b.running_lastcost
from mm_itrghd a, mm_itrgdt b where (a.objid=b.header_id) and
(b.item_id=1200) and (b.wh_id=1) and
((a.postdate<'2010-09-05 00:00:00') or ((a.postdate='2010-09-05 00:00:00') and (a.objid<50000)))
order by a.postdate desc, a.objid desc, b.calctyp desc, b.objid desc

As you see, in order by section, we use desc. I have an descending index, but my query plan does not use it.
It only use index Table A (a.objid) and Table B (b.item_id, b.wh_id)
Is there something i missed? What index do you think should i create?



Index for Table A (mm_itrghd)


(TR_CODE, DOC_ID) Ascending
(OBJID) Ascending
(TR_CODE) Ascending
(POSTDATE) Ascending
(POSTDATE, OBJID) Ascending
(POSTDATE, OBJID) Descending




Index for Table B (mm_itrgdt)

(HEADER_ID) Ascending
(ITEM_ID) Ascending
(WH_ID) Ascending
(LOT_NO) Ascending
(SERIAL_NO, ITEM_ID) Ascending
(HEADER_ID, ITEM_ID, WH_ID, SERIAL_NO, LOT_NO) Ascending
(HEADER_ID, ITEM_ID, WH_ID) Ascending
(CALCTYP, OBJID) Ascending
(ITEM_ID, WH_ID) Ascending
(CALCTYP, OBJID, ITEM_ID, WH_ID) Ascending
(CALCTYP, OBJID) Descending
(OBJID, ITEM_ID, WH_ID) Descending
(OBJID) Descending




Thanks in advance

Regards,
Reynaldi