How Do I...How Can I Use Distinct For Not Showing Same Productcode Again And How We Can Make Stock Report Trough This Query

select isNull(Purchase.ProductCode,0)as'Product Code',
isNull(ps.Quantity,0) as 'Opening Stock',
isNull(Purchase.Quantity,0) as 'Purchase Quantity',  
isNull(Saleitem.Quantity,0) 'Sale Quantity'   
,isNull(ps.Quantity + Purchase.Quantity - Saleitem.Quantity,0) as 'Closing Stock',
convert(date,Purchase.date,101)as'Date'
from 
(select ProductCode,Quantity,CONVERT(date,DateTime,101)date  from stocktable
where Status='Purchase Entry' 
and  ProductCode = 4 
group by  ProductCode,Quantity,CONVERT(date,DateTime,101))Purchase 
Full join
(
select ProductCode,convert(date,DateTime,101)as date,SUM(quantity)as Quantity
from Stocktable 
where Status='Sale Entry'
group by  ProductCode ,convert(date,DateTime,101) 
)Saleitem
on Saleitem.ProductCode='4'
full join
(
select p.Quantity,p.productcode,p.vendorcode from purechaseStockreport p
group by p.Quantity ,p.productcode,p.vendorcode
)ps
on ps.productcode = '4'
or ps.productcode = '4'
DISTIselect isNull(Purchase.ProductCode,0)as'Product Code',
isNull(ps.Quantity,0) as 'Opening Stock',
isNull(Purchase.Quantity,0) as 'Purchase Quantity',  
isNull(Saleitem.Quantity,0) 'Sale Quantity'   
,isNull(ps.Quantity + Purchase.Quantity - Saleitem.Quantity,0) as 'Closing Stock',
convert(date,Purchase.date,101)as'Date'
from 
(select ProductCode,Quantity,CONVERT(date,DateTime,101)date  from stocktable
where Status='Purchase Entry' 
and  ProductCode = 4 
group by  ProductCode,Quantity,CONVERT(date,DateTime,101))Purchase 
Full join
(
select ProductCode,convert(date,DateTime,101)as date,SUM(quantity)as Quantity
from Stocktable 
where Status='Sale Entry'
group by  ProductCode ,convert(date,DateTime,101) 
)Saleitem
on Saleitem.ProductCode='4'
full join
(
select p.Quantity,p.productcode,p.vendorcode from purechaseStockreport p
group by p.Quantity ,p.productcode,p.vendorcode
)ps
on ps.productcode = '4'
or ps.productcode = '4'NIC