Database

1. Open, read, then close each of your datareaders in sequence.
2. Execute all of the queries using a single datareader (e.g. "select * from a ; select * from b ; select * from c"). The datareader is able to process multiple resultsets (for many database products).
3. Read each of your queries into a DataSet object then do whatever processing you need against the DataSet.
4. Open multiple database connections.

SELECT SUM(field) AS [expression]<br />
FROM table<br />
[WHERE ...]<br />
[GROUPBY ...]<br />
[HAVING ...]

select a.ClientID, a.ClientName, b.YTDGross, b.YTDNetCom,
  b.YTDNetInt, b.CSCost, b.OtherCost,
  (b.YTDNetCom + b.YTDNetInt) as YTDNetRev,
  (b.CSCost + b.OtherCost) as TotalAlloCost,
  (b.YTDNetRev - (b.CSCost + b.OtherCost)) as TotalNetRev,
  sum(c.YTDNetRev - (c.CSCost + c.OtherCost)) as RunningTotal
from tblClients as a, tblData as b, tblData as c
where a.ClientName = b.ClientName
and a.ClientName >= c.ClientName
group by a.ClientName, a.ClientID, b.YTDGross, b.YTDNetCom, 
  b.YTDNetInt, b.CSCost, b.OtherCost
order by a.ClientName, a.ClientID

DataView t=new DataView(someTable);<br />
t.RowStateFilter=DataViewRowState.CurrentRows;<br />
		<br />
debug.WriteLine("Rows Count before deletion= "+ t.Count);<br />
t[0].Delete();<br />
debug.WriteLine("Rows Count after deletion = "+ t.Count);