Count Distinct from Differnet Table

[JazzBass]

I'm trying to get a distinct count (example cars) that are stored in another table. I know in Access you need something like:

Select count(cartype) from (Select distinct(cartype) from DailyData)

But, I have the following SQL pieced together and all I can get is count (includes duplicates)

SELECT a.wDate, Sum(a.Sales) AS TotalSales, Count(b.cartype) as DiffCars 
FROM DailyData a left join AllCarTypes b on a.wDate = b.wDate
where a.wDate = #06-27-2001#
GROUP BY a.wDate

I don't know the syntax to get the distinct count in my query.

Anyone have any ideas?