คำถามและคำตอบต่อเดือน ไม่จำเป็นต้องใช้ทุกตาราง
Questions and Answers per month.It is not neccessary to use all the tables.
 PostHistoryTypes:  Id [ number]  Name [ text] 
SELECT DATEADD(month, DATEDIFF(month, @start, CreationDate), @start) AS "month", SUM(CASE WHEN PostTypeId = 1 THEN 1 ELSE 0 END) AS "questions", SUM(CASE WHEN PostTypeId = 2 THEN 1 ELSE 0 END) AS "answers" FROM Posts WHERE (PostTypeId = 1 OR PostTypeId = 2) AND CreationDate >= @start AND CreationDate < @stop AND Score = 0 GROUP BY DATEADD(month, DATEDIFF(month, @start, CreationDate), @start) ORDER BY DATEADD(month, DATEDIFF(month, @start, CreationDate), @start)