Update 變更紀錄

1. 先列出資料表中的紀錄。

   mariadb root@localhost:dyw> select * from tbl;                                  
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | PHP     | david  | 2020-01-28      |
   | 2  | MariaDB | dywang | 2020-01-01      |
   | 3  | Linux   | linux  | 2020-01-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.031s
   

2. 變更紀錄 id=1 的 title 為 python。

   mariadb root@localhost:dyw> update tbl set title='python' where id=1;           
   Query OK, 1 row affected
   Time: 0.006s
   

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

   mariadb root@localhost:dyw> select * from tbl;                                  
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | python  | david  | 2020-01-28      |
   | 2  | MariaDB | dywang | 2020-01-01      |
   | 3  | Linux   | linux  | 2020-01-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.029s
   

4. 一次更新一筆紀錄的 2 個欄位。

   mariadb root@localhost:dyw> update tbl set title='c++',author='peter' where id=1
                               ;                                                   
   Query OK, 1 row affected
   Time: 0.008s
   

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@localhost:dyw> select * from tbl;                                  
   +----+---------+--------+-----------------+
   | id | title   | author | submission_date |
   +----+---------+--------+-----------------+
   | 1  | c++     | peter  | 2020-01-28      |
   | 2  | MariaDB | dywang | 2020-01-01      |
   | 3  | Linux   | linux  | 2020-01-11      |
   +----+---------+--------+-----------------+
   
   3 rows in set
   Time: 0.030s