Nested Select, And Table Joint

Hi Guys

Am new to sql, and I wold appreciate help with optimising the folloing example. The result of the example should be to list a result with details of the Column names:

OPBal| Receipt| IssTrns| Transfer| ClBal

SELECT dbo.inventory.location, dbo.inventory.itemnum,
(select sum(dbo.matrectrans.linecost) where dbo.matrectrans.issuetype LIKE 'RECEIPT' ) As Receipt,
( select sum(dbo.matrectrans.linecost)where dbo.matrectrans.issuetype LIKE 'TRANSFER' ) As Transfer,
( select(dbo.IST_ITEMDETAIL.curbal*dbo.IST_ITEMDETAIL.avgcost)where dbo.IST_ITEMDETAIL.logdate='2006-07-20' ) As OpBal,
( select (IST_ITEMDETAIL.curbal*IST_ITEMDETAIL.avgcost)where IST_ITEMDETAIL.logdate='2006-08-21' ) As ClBal,
( sum(matusetrans.linecost) ) As IssTrnf
FROM dbo.matrectrans, dbo.matusetrans, dbo.IST_ITEMDETAIL , ( dbo.inventory inner JOIN dbo.item
ON dbo.inventory.itemnum = dbo.item.itemnum AND dbo.inventory.orgid = dbo.item.orgid )

WHERE dbo.inventory.location = dbo.matusetrans.storeloc
AND dbo.inventory.itemnum = dbo.matrectrans.itemnum AND dbo.inventory.siteid = dbo.matrectrans.siteid

OR dbo.inventory.location = dbo.matrectrans.tostoreloc AND dbo.inventory.itemnum = dbo.matusetrans.itemnum
AND dbo.inventory.siteid = dbo.matusetrans.siteid OR dbo.inventory.location = dbo.matrectrans.fromstoreloc

OR
dbo.inventory.location = dbo.ist_itemdetail.location AND dbo.inventory.itemnum = dbo.ist_itemdetail.itemnum
GROUP BY dbo.inventory.location, dbo.inventory.itemnum,dbo.matrectrans.issuetype,(dbo.IST_ITEMDETAIL.curbal*dbo.IST_ITEMDETAIL.avgcost),
dbo.IST_ITEMDETAIL.logdate,dbo.IST_ITEMDETAIL.curbal,dbo.IST_ITEMDETAIL.avgcost