SQL Addition of two Temp Tables - sql

Question

I have two temp tables that are counting a number of IDs. I want to combine those tables to give the count for each and then add those together. This is what I have so far.
if object_id('tempdb..#order') is not null drop table #order
select count (a.patientSID) as 'Order Count'
into #order
from CPRSOrder.CPRSOrder a
join sstaff.SStaff b on b.staffSID = a.EnteredbyStaffSID
join spatient.spatient c on c.patientSID = a.patientSID
where b.staffName = xxxxxxxx
and a.enteredDateTime >= '20180801' and a.enteredDateTime <= '20180828'
if object_id('tempdb..#note') is not null drop table #note
select count (a.patientSID) as 'Note Count'
into #note
from tiu.tiudocument a
join sstaff.SStaff b on b.staffSID = a.EnteredbyStaffSID
--join spatient.spatient c on c.patientSID = a.patientSID
where b.staffName = xxxxxxxx
and a.episodeBeginDateTime >= '20180801' and a.episodeBeginDateTime <= '20180828'
select (select [Note Count] from #note) as 'Note Count',
(select [Order Count] from #order) as 'Order Count',
sum((select [Order Count] from #order) + (select [Note Count] from #note)) as Total

Answer 1

Remove the sum(), unless you want to aggregate. Also, since the tables contain only one row each, this could be simplified a little by using a cross join.
SELECT n.[Note Count],
o.[Order Count],
n.[Note Count] + o.[Order Count] [Total]
FROM #note n
CROSS JOIN #order o;

Answer 2

While there's nothing syntactically wrong with selecting a single column from a temp table, what is clear is you are using an entire temp table to save a single value, an aggregated sum. An integer variable can also hold a count. For example:
DECLARE #order int =
(
select count (a.patientSID)
from CPRSOrder.CPRSOrder a
join sstaff.SStaff b on b.staffSID = a.EnteredbyStaffSID
join spatient.spatient c on c.patientSID = a.patientSID
where b.staffName = xxxxxxxx
and a.enteredDateTime >= '20180801' and a.enteredDateTime <= '20180828'
)
DECLARE #note int = (
select count (a.patientSID)
from tiu.tiudocument a
join sstaff.SStaff b on b.staffSID = a.EnteredbyStaffSID
--join spatient.spatient c on c.patientSID = a.patientSID
where b.staffName = xxxxxxxx
and a.episodeBeginDateTime >= '20180801' and a.episodeBeginDateTime <= '20180828'
)
SELECT #note AS [note count]
,#order AS [order count]
,#order + #note AS [total]