### **有幾位使用者** ```sql= SELECT COUNT(ID) FROM users ``` ### **有幾位是出題者** ```sql= SELECT COUNT(DISTINCT(authod_id)) FROM questions ``` ### **有幾位是出題者+幾位出題者(欄位名稱更改)** ```sql= SELECT COUNT(ID) AS question_cnt, COUNT(DISTINCT authod_id) AS　author_cnt FROM questions ``` ### **題庫裡有多少題目** ```sql= SELECT COUNT(ID) FROM questions ```