Divide and sum in SQL - sql

Question

I got this code and in this code I do a sum of the slow and fast driver. My Problem is I must divide this sum with the normal driver. I don´t know how I can do a division in this statement:
Select *
FROM (
Select date as Datetime, tevent.name as Event, level = case
when levelname = 'High' then 'High'
when levelname = 'Normal' then 'Normal'
when shiftname = 'Low' then 'Low'
end, SUM(value) as sum
from tCount inner join tEvent ON tCount.eventid = tevent.id
where Name in ('Drive Fast', 'Drive Slow')
and date > getdate() -1
and tevent.Name in ('E01','E02','E03','E04','E05','E06','E07','E08')
and CalName = 'Drive'
group by tevent.name, date, levelname
) as s
PIVOT
(
SUM(sum)
FOR Event IN (E01,E02,E03,E04,E05,E06,E07,E08)
) as p
order by Datetime, level
And Then I put the same Select statement with the normal driver :
... from tCount inner join tEvent ON tCount.eventid = tevent.id
where Name in ('drive normal') ...
And I would like to make a division like this:
(Sum('drive fast' + 'drive slow')/Sum('drive normal')) * 100

Answer 1

There is a simpler way to include different cases in different sums inside a SQL statement: sum a case, like in the below calculation of percent:
Select ...
, SUM(case Name
when 'drive fast' then Value
when 'drive slow' then value
else 0 end)
/ SUM(case Name
when 'drive normal' then value
else 0 end) * 100 as percentage
from ...
where ...
group by ...;
As I lack data to test this code, I created a query on the CARS table SAS delivers as training material, implementing the same principle.
select Cylinders
, sum(case origin when 'USA' then EngineSize
when 'Asia' then EngineSize
else 0.0 end)
/ sum(case origin when 'Europe' then EngineSize
else 0.0 end)
* 100 as percentage
from sasHelp.cars
where Cylinders in (4, 5, 6, 12)
group by Cylinders