แต่ละระดับมีผู้ใช้กี่คน?ไม่จำเป็นต้องใช้ตารางทั้งหมด
How many users have each level of badge?.It is not neccessary to use all the tables.
 SuggestedEdits:  Id [ number]  PostId [ number]  CreationDate [ time]  ApprovalDate [ time]  RejectionDate [ time]  OwnerUserId [ number]  Comment [ text]  Text [ text]  Title [ text]  Tags [ text]  RevisionGUID [ other] 
SELECT CASE WHEN Class = 1 THEN 'Gold' WHEN Class = 2 THEN 'Silver' WHEN Class = 3 THEN 'Bronze' END AS class, TagBased, COUNT(DISTINCT UserId) FROM Badges GROUP BY Class, TagBased