从 MySQL 表中删除索引
mysqlmysqli database更新于 2024/2/11 14:06:00
要从 MySQL 表中删除索引，语法如下 −
alter table yourTableName drop index `yourIndexName`;
首先我们创建一个表 −
Mysql> create table DemoTable1469 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(40), -> StudentAge int -> ); Query OK, 0 rows affected (0.78 sec)
以下是在列名上添加索引的查询 −
mysql> create index `Student Name_Index` on DemoTable1469(StudentName); Query OK, 0 rows affected (0.33 sec) Records: 0 Duplicates: 0 Warnings: 0
让我们检查一下表描述 −
mysql> desc DemoTable1469;
这将产生以下输出 −
+-------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+-------------+------+-----+---------+----------------+ | StudentId | int(11) | NO | PRI | NULL | auto_increment | | StudentName | varchar(40) | YES | MUL | NULL | | | StudentAge | int(11) | YES | | NULL | | +-------------+-------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec)
以下是删除索引的查询 −
mysql> alter table DemoTable1469 drop index `Student Name_Index`; Query OK, 0 rows affected (0.23 sec) Records: 0 Duplicates: 0 Warnings: 0
让我们再次检查表格描述 −
mysql> desc DemoTable1469;
这将产生以下输出 −
+-------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+-------------+------+-----+---------+----------------+ | StudentId | int(11) | NO | PRI | NULL | auto_increment | | StudentName | varchar(40) | YES | | NULL | | | StudentAge | int(11) | YES | | NULL | | +-------------+-------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec)
