declare @price table(id int identity( 1 , 1 ), post char( 5 ),item varchar( 10 ))
declare @price_val table(id int identity( 1 , 1 ),parent int,dates datetime,val decimal( 18 , 3 ))
insert @price(post,item) 
select '???','item1' union all
select '???','item2' union all
select '???','item3' 
insert @price_val(parent,dates,val)
select  1 ,'20021010' , 28 . 75  union all
select  1 ,'20021110', 29 . 75  union all
select  1 ,'20021121', 30 . 75  union all
select  1 ,'20021122', 31 . 75  union all
select  2 ,'20021010', 128 . 75  union all
select  2 ,'20021110', 129 . 75  union all
select  2 ,'20021121', 130 . 75  union all
select  2 ,'20021122', 130 . 75  
select * from @price
select * into #t
from @price_val
where dates > '20021120' and val> 0 
select t.*,max(#t.dates) 
from	(select parent,min(val) val
	from #t
	group by parent) t join 
            #t on t.parent=#t.parent and t.val=#t.val
group by t.parent,t.val
 -- из условия max(pos)---
 
select *
from (select p.id,p.post,p.item
      from (select item,max(post) from @price group by item)i
               join @price p on i.item=p.item and i.post=p.post) pr
      join
	(select t.*,max(#t.dates)  -- #t.id если понадобится
 
	 from	(select parent,min(val) val
		 from #t
		 group by parent) t join 
	            #t on t.parent=#t.parent and t.val=#t.val
	 group by t.parent,t.val)pv 
      on pr.id=pv.parent

select b.item,a.date,a1.value,b.post
from price b (nolock)
       inner join price_val a
       on a.id=b.id
       and a.id=(select top  1  a1.parent
                      from price_val a1 (nolock), price b1 (nolock)
                      where a1.date >'01.11.02' and a1.value> 0  and a1.parent=b1.id and b1.item=b.item
                      order by  a2.value)
order by b.item