DROP 刪除

1. DROP 刪除資料表 tbl 欄位 c。

   mariadb root@localhost:dyw> alter table tbl drop c;                             
   You're about to run a destructive command.
   Do you want to proceed? (y/n): y
   Your call!
   Query OK, 0 rows affected
   Time: 0.116s
   

2. 再查看資料表 tbl 的欄位格式。

   mariadb root@localhost:dyw> show columns from tbl;                              
   +-----------------+--------------+------+-----+---------+----------------+
   | Field           | Type         | Null | Key | Default | Extra          |
   +-----------------+--------------+------+-----+---------+----------------+
   | bi              | bigint(20)   | YES  |     | <null>  |                |
   | id              | int(11)      | NO   | PRI | <null>  | auto_increment |
   | title           | varchar(100) | NO   |     | <null>  |                |
   | author          | varchar(40)  | NO   |     | <null>  |                |
   | submission_date | date         | YES  |     | <null>  |                |
   +-----------------+--------------+------+-----+---------+----------------+
   
   5 rows in set
   Time: 0.026s