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Legal Studies在 MySQL 中將 StudentName 列名更改為 FirstName？
將 CHANGE 用作 ALTER 語句。讓我們首先建立一個表 -
mysql> create table DemoTable -> ( -> StudentName varchar(100), -> Age int -> ); Query OK, 0 rows affected (0.84 sec)
現在查看錶的說明 -
mysql> desc DemoTable;
輸出
這會產生以下輸出 -
+----------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+-------+ | StudentName | varchar(100) | YES | | NULL | | | Age | int(11) | YES | | NULL | | +----------------+--------------+------+-----+---------+-------+ 2 rows in set (0.25 sec)
以下是用 ALTER 編寫的查詢 -
mysql> alter table DemoTable -> add column Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> add column CountryName varchar(100) after Age, -> change column StudentName FirstName varchar(200); Query OK, 0 rows affected (1.51 sec) Records: 0 Duplicates: 0 Warnings: 0
現在再次查看錶的說明 -
mysql> desc DemoTable;
輸出
這會產生以下輸出 -
+-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | FirstName | varchar(200) | YES | | NULL | | | Age | int(11) | YES | | NULL | | | CountryName | varchar(100) | YES | | NULL | | | Id | int(11) | NO | PRI | NULL | auto_increment | +-------------+--------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec)
更新於: 30-6月-2020
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