For each site, show the average number of votes per post (questions and answers alike)
Q&A for those who study, teach, research and apply economics and econometrics
SELECT Count(*) AS [Votes], Count(CASE VoteTypeID WHEN 2 THEN 1 END) AS [Upvotes], Count(CASE VoteTypeID WHEN 3 THEN 1 END) AS [Downvotes] FROM Votes WHERE (VoteTypeId = 2 OR VoteTypeId = 3)