Count if an event occured each day of the year from date ranges 1

[waubain]

Using prescription data and I am trying to count if a person had the opportunity to take at least 1 pill on each day of a period of interest, which in my current project is 365 days starting from an index date. I found this Example and spent several hours dissecting it, but it is beyond my understanding level. I am not interested in the max counts per interval, but I would just count the intervals where the count <> 0.
Our db has a dimDate table and has a DateID column and a date column smalldatetime

Here is some hypothetical prescription data

DECLARE @StudyStartDate date = '2010-01-01' --inclusive
DECLARE @StudyEndDate date = '2011-01-01' --exclusive
CREATE TABLE #temp (PatientID int, RxFillID int, DrugID int, RxFillDate date, DaysSupply int)
INSERT INTO #temp VALUES
 (1,1,1001,'2010-01-01',30)
,(1,2,1001,'2010-03-01',30)
,(1,3,1001,'2010-05-01',30)
,(1,4,1001,'2010-07-01',30)
,(1,5,1001,'2010-09-01',30)
,(1,1,1002,'2010-04-01',30)
,(1,2,1002,'2010-06-01',30)
,(1,3,1002,'2010-08-01',30)
,(1,4,1002,'2010-10-01',30)
,(2,1,1003,'2010-01-01',90)
,(2,2,1003,'2010-05-01',60)
,(2,1,1004,'2010-05-01',90)

In the above example, patient#1 the two prescriptions never overlap, so that PrescriptionDay count would be 270, but patient #2 has prescriptions overlap so the opportunity on the overlapping days of the different prescriptions is still a 1, so the patients PrescriptionDay count would be 180. I hope that makes sense. The EndDate for each prescription fill would be DATEADD(d, [DaysSupply], [RxFillDate].

I may be looking through several million records. I do not have permissions in the db I am working to create a function or procedure.

I would appreciate any guidance, I am at a loss on where to start. Thank you in advance.

You don't know what you don't know...

 

[mharroff]

SELECT t.PatientID, COUNT(DISTINCT d.CalendarDate)
FROM Dates d
JOIN #Temp t
ON d.CalendarDate BETWEEN t.RxFillDate AND DATEADD(DAY,t.DaysSupply -1,t.RXFillDate)
WHERE d.CalendarDate >= @StudyStartDate
AND d.CalendarDate < @StudyEndDate
GROUP BY t.PatientID

 

[waubain]

mharroff,
This is exactly what I was looking for in a much smaller package than what I was expecting based on the example.
Thank you very much for the prompt response and your expertise.

You don't know what you don't know...