MySQL MAX() 函式教學：最大值查詢與分組統計實例

MAX() 聚合函式用於找出指定欄位的最大值，用法與 MIN() 對稱。本文以相同的 employee_tbl 資料示範。

資料準備

mysql> SELECT * FROM employee_tbl;
+------+------+------------+--------------------+
| id   | name | work_date  | daily_typing_pages |
+------+------+------------+--------------------+
| 1    | John | 2007-01-24 | 250                |
| 2    | Ram  | 2007-05-27 | 220                |
| 3    | Jack | 2007-05-06 | 170                |
| 3    | Jack | 2007-04-06 | 100                |
| 4    | Jill | 2007-04-06 | 220                |
| 5    | Zara | 2007-06-06 | 300                |
| 5    | Zara | 2007-02-06 | 350                |
+------+------+------------+--------------------+

全表最大值

mysql> SELECT MAX(daily_typing_pages) FROM employee_tbl;
+-------------------------+
| MAX(daily_typing_pages) |
+-------------------------+
| 350                     |
+-------------------------+

分組最大值：GROUP BY name

mysql> SELECT id, name, work_date, MAX(daily_typing_pages) 
    -> FROM employee_tbl GROUP BY name;
+------+------+------------+-------------------------+
| id   | name | work_date  | MAX(daily_typing_pages) |
+------+------+------------+-------------------------+
| 3    | Jack | 2007-05-06 | 170                     |
| 4    | Jill | 2007-04-06 | 220                     |
| 1    | John | 2007-01-24 | 250                     |
| 2    | Ram  | 2007-05-27 | 220                     |
| 5    | Zara | 2007-06-06 | 350                     |
+------+------+------------+-------------------------+

同 MIN()，非聚合欄位值取自群組第一筆，不一定對應最大值那一列。

MIN 與 MAX 合用

mysql> SELECT MIN(daily_typing_pages) least, MAX(daily_typing_pages) max 
    -> FROM employee_tbl;
+-------+------+
| least | max  |
+-------+------+
| 100   | 350  |
+-------+------+

應用場景

• 監控系統：即時取得指標極值。
• 資料品質檢查：偵測異常極大/極小值。
• 統計報表：呈現數據範圍。