How to reduce logical count and scan count for a select query

Question

hi,
I have two tables one is master and other is history. i need to combine this two tables into one temporary table.
I am using the below query to create temp table.
Select * into temporders
from
(select * from orders
union
select * from ordershistory) b
where updateon= (select max(updateon)from (select updateon,name,units,subunits from orders
union
select updateon,name,units,subunits from ordershistory) a
where updateon <='11/08/2008 11:18 AM' and a.name=b.name and a.units=b.units and a.subunits=b.subunits group by name,units,subunits)
order by report,subunitsorder
the statistics for this query:
SQL Server parse and compile time:
CPU time = 47 ms, elapsed time = 62 ms.
Table 'Worktable'. Scan count 556, logical reads 1569, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'ORDERSHISTORY'. Scan count 116, logical reads 339, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'ORDERS'. Scan count 116, logical reads 285, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
SQL Server Execution Times:
CPU time = 32 ms, elapsed time = 63 ms.
(115 row(s) affected)
you see logical reads and scan count for worktable(temporary) is quite high.
So anyone can give a solution for reduce the scan count and logical reads.
NOTE: name,units, subunits,updateon columns have primarykey

Answer 1

SQL ServerAm i reading it properly? :(
This is Oracle Forum And not the SQL Server.
Regards.
Satyaki De.