Update 變更紀錄

1. 先列出資料表中的紀錄。

   MariaDB root@(none):dyw> select * from tbl;
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | PHP     | david  | 2025-11-10      |
   | 2  | Linux   | linux  | 2025-11-10      |
   | 3  | Mariadb | dywang | 2025-11-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.037s
   

2. 變更紀錄 id=1 的 title 為 Python。

   MariaDB root@(none):dyw> update tbl set title='Python' where id=1;
   Query OK, 1 row affected
   Time: 0.028s
   

3. 再列出資料表中的紀錄，紀錄 id=1 的 title 已更新為 Python。

   MariaDB root@(none):dyw> select * from tbl;
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | Python  | david  | 2025-11-10      |
   | 2  | Linux   | linux  | 2025-11-10      |
   | 3  | Mariadb | dywang | 2025-11-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.017s
   

4. 一次更新一筆紀錄的 2 個欄位。

   MariaDB root@(none):dyw> update tbl set title='C++',author='peter' where id=1;
   Query OK, 1 row affected
   Time: 0.013s
   

5. 再列出資料表中的紀錄，紀錄 id=1 的 title 及 author 2 個欄位都已更新。

   MariaDB root@(none):dyw> select * from tbl;
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | C++     | peter  | 2025-11-10      |
   | 2  | Linux   | linux  | 2025-11-10      |
   | 3  | Mariadb | dywang | 2025-11-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.012s