SQL Sum of last X Sum of records

Question

I\'ve looked for a while and I cannot find the answer to this question (maybe I\'m not searching the correct terms or something). Basically, I have a database that has any n

Answer 1

Here is an idea using correlated subqueries:

with bydays as (<your query here>)
select bd.*,
       (select sum(NumMeasured) from (select top 100 * from bydays bd2 where bd2.date <= bd.date order by date desc) t
       ) as Measured100,
       (select sum(NumPassingd) from (select top 100 * from bydays bd2 where bd2.date <= bd.date order by date desc) t
       ) as Measured100
from bydays

Answer 2

To get your last 100 dates,

SELECT TOP(100) DISTINCT date FROM yield ORDER BY date desc

You can simplify your first query with something as simple as

SELECT date, SUM(passing) as numpassing, SUM(Measured) as nummeasured
FROM yield
GROUP BY date

If you need the sum from now until 100 days ago

SELECT SUM(passing) as npassing, SUM(measured) as nmeasured
FROM yield
WHERE date >= DATEADD(d,100,CURRENT)

And if you need the sum from the last 100 dates

SELECT SUM(passing) as npassing, SUM(measured) as nmeasured
FROM yield
WHERE date IN (SELECT TOP 100 date FROM yield WHERE date <= '04/05/2013' ORDER BY date desc)