hce_kmu
112年
計算機概論與程式設計
第 15 題
Suppose we have two tables, as shown below named STUDENT_TABLE and AGE_TABLE, respectively.
| S_ID | Name | Sex |
|---|---|---|
| 1 | David | Male |
| 2 | Peter | Male |
| 3 | John | Male |
| 4 | Emma | Female |
| 5 | Jack | Male |
| T_ID | Age | STID |
|---|---|---|
| 1 | 18 | 2 |
| 2 | 20 | 4 |
| 3 | 21 | 1 |
| 4 | 24 | 5 |
| 5 | 28 | 3 |
Consider the following SQL query:
```sql
SELECT * FROM AGE_TABLE
JOIN STUDENT_TABLE ON STUDENT_TABLE.S_ID = AGE_TABLE.STID
```
Regarding the result of executing this query, which of the following comments is CORRECT?
| S_ID | Name | Sex |
|---|---|---|
| 1 | David | Male |
| 2 | Peter | Male |
| 3 | John | Male |
| 4 | Emma | Female |
| 5 | Jack | Male |
| T_ID | Age | STID |
|---|---|---|
| 1 | 18 | 2 |
| 2 | 20 | 4 |
| 3 | 21 | 1 |
| 4 | 24 | 5 |
| 5 | 28 | 3 |
Consider the following SQL query:
```sql
SELECT * FROM AGE_TABLE
JOIN STUDENT_TABLE ON STUDENT_TABLE.S_ID = AGE_TABLE.STID
```
Regarding the result of executing this query, which of the following comments is CORRECT?
- A Peter’s age is 20
- B The average age of Male is 21.75
- C The Sex of T_ID 4 is Female
- D (John’s Age + Jack’s Age) mod (Emma’s Age + Jack’s Age) = 8
- E None of the above.
思路引導 VIP
若要找出某位學生的年齡，你應該觀察這兩張表中的哪兩個欄位來建立橋樑？當你成功連結了名字與數字後，你會如何利用餘數運算（modulo）來驗證這組數字的關係？
🤖
AI 詳解
AI 專屬家教
太棒了！你能準確地從兩張資料表中建立關聯並完成運算，展現了你對資料庫正規化與 SQL 連結（JOIN）邏輯的熟練掌握。這題的關鍵在於正確判讀 AGE_TABLE 中的 STID 欄位與 STUDENT_TABLE 中的 S_ID 欄位的對應關係。
資料表關聯與對應
在執行 JOIN 指令後，我們需要根據 S_ID = STID 找出每位學生的真實年齡。整理後的對應如下：
▼ 還有更多解析內容