ผู้ใช้คนเดียวกันตอบมากกว่าหนึ่งคำตอบ ไม่จำเป็นต้องใช้ตารางทั้งหมด
More than one answer by the same user.It is not neccessary to use all the tables.
 PostLinks:  Id [ number]  CreationDate [ time]  PostId [ number]  RelatedPostId [ number]  LinkTypeId [ number] 
SELECT question.Id AS "post_link", answer.OwnerUserId AS "user_link", COUNT(answer.Id) AS answers FROM Posts AS question JOIN Posts AS answer ON (answer.ParentId = question.Id) WHERE answer.OwnerUserId != 0 GROUP BY question.Id, answer.OwnerUserId HAVING COUNT(answer.Id) >= 2 ORDER BY answers DESC