จำนวนการแก้ไขโดยเฉลี่ยต่อโพสต์ ไม่จำเป็นต้องใช้ตารางทั้งหมด
Average amount of revisions per post.It is not neccessary to use all the tables.
 Posts:  Id [ number]  PostTypeId [ number]  AcceptedAnswerId [ number]  ParentId [ number]  CreationDate [ time]  DeletionDate [ time]  Score [ number]  ViewCount [ number]  Body [ text]  OwnerUserId [ number]  OwnerDisplayName [ text]  LastEditorUserId [ number]  LastEditorDisplayName [ text]  LastEditDate [ time]  LastActivityDate [ time]  Title [ text]  Tags [ text]  AnswerCount [ number]  CommentCount [ number]  FavoriteCount [ number]  ClosedDate [ time]  CommunityOwnedDate [ time]  ContentLicense [ text] 
SELECT revisions.Month, revisions."amount_of_revisions" / CAST(sum_posts."amount_of_posts" AS FLOAT) FROM (SELECT Month = DATEADD(MONTH, DATEDIFF(MONTH, 0, CreationDate), 0), 'Amount of revisions' = COUNT(Id) FROM PostHistory GROUP BY DATEADD(MONTH, DATEDIFF(MONTH, 0, CreationDate), 0)) AS revisions INNER JOIN (SELECT Month, 'Amount of posts' = SUM(posts) OVER (ORDER BY Month rows BETWEEN unbounded preceding AND CURRENT ROW) FROM (SELECT Month = DATEADD(MONTH, DATEDIFF(MONTH, 0, CreationDate), 0), Posts = COUNT(Id) FROM Posts GROUP BY DATEADD(MONTH, DATEDIFF(MONTH, 0, CreationDate), 0)) AS new_posts_per_month) AS sum_posts ON revisions.Month = sum_posts.Month ORDER BY Month