declare @tbl1 table (
  item   varchar(10),
  wt     varchar(10),
  seqno  int,
  [date] date
  )

declare @tbl2 table (
  item   varchar(10),
  wt     varchar(10),
  seqno  int,
  [date] date
  )

insert into @tbl1
values
  ('item1', 'wt1', 1, '5/30/2012'),
  ('item2', 'wt2', 1, '5/30/2012'),
  ('item3', 'wt3', 1, '5/30/2012'),
  ('item4', 'wt4', 2, '5/30/2012'),
  ('item5', 'wt5', 2, '5/30/2012'),
  ('item6', 'wt6', 1, '5/30/2012')

insert into @tbl2
values
  ('item1', 'wt1', 1, '5/29/2012'),
  ('item2', 'wt2', 1, '5/29/2012'),
  ('item3', 'wt3', 1, '5/29/2012'),
  ('item4', 'wt4', 2, '5/29/2012'),
  ('item5', 'wt5', 2, '5/29/2012'),
  ('item6', 'wt6', 1, '5/29/2012'),
  ('item1', 'wt1', 1, '5/28/2012'),
  ('item2', 'wt2', 1, '5/28/2012'),
  ('item3', 'wt3', 1, '5/28/2012'),
  ('item4', 'wt4', 2, '5/28/2012'),
  ('item5', 'wt5', 2, '5/28/2012'),
  ('item6', 'wt6', 1, '5/28/2012'),
  ('item1', 'wt1', 1, '5/27/2012'),
  ('item2', 'wt2', 1, '5/27/2012'),
  ('item3', 'wt3', 1, '5/27/2012'),
  ('item4', 'wt4', 2, '5/27/2012'),
  ('item5', 'wt5', 2, '5/27/2012'),
  ('item6', 'wt6', 1, '5/27/2012')

;with LatestHistory
as(
  select a.item, a.wt, a.seqno
  from (
    select item, wt, seqno, row_number() over(partition by item, seqno order by [date] DESC) rn
    from @tbl2
    ) a
  where a.rn = 1
  )
select
  today.item, today.wt, today.seqno, history.wt
from
  @tbl1 today
inner join
  LatestHistory history
    on  today.item = history.item
    and today.seqno = history.seqno

SELECT t1.*,t2.[LatestInsertedDate] 
FROM @tbl1 t1
CROSS APPLY (SELECT MAX([date]) AS LatestInsertedDate
             FROM @tbl2
             WHERE item = t1.item
             AND wt = t1.wt
             AND [seq no] = t1.[seq no]
            )t2