คะแนนเฉลี่ยต่อแท็ก (นับ) ไม่จำเป็นต้องใช้ตารางทั้งหมด
Average Score Per Tag (with count).It is not neccessary to use all the tables.
 ReviewRejectionReasons:  Id [ number]  Name [ text]  Description [ text]  PostTypeId [ number] 
SELECT TagName, AVG(Score) AS Score, COUNT(Posts.Id) AS Number FROM Posts INNER JOIN PostTags ON PostTags.PostId = Posts.Id INNER JOIN Tags ON Tags.Id = PostTags.TagId GROUP BY TagName ORDER BY COUNT(Posts.Id) DESC, AVG(Score) DESC, TagName