.ไม่จำเป็นต้องใช้ทุกตาราง
.It is not neccessary to use all the tables.
 PostTags:  PostId [ number]  TagId [ number] 
SELECT q.Cnt AS AnswerCount, COUNT(*) AS QuestionCount, COUNT(*) * 100.0 / MIN(TotalQuestions) AS "Percent" FROM (SELECT (SELECT COUNT(*) FROM Posts AS a WHERE a.PostTypeId = 1) AS TotalQuestions, (SELECT COUNT(*) FROM Posts AS a WHERE a.ParentId = q.Id AND a.PostTypeId = 2) AS Cnt FROM Posts AS q WHERE q.PostTypeId = 1) AS q GROUP BY q.Cnt ORDER BY q.Cnt