Remove index from a MySQL table

To remove index from a MySQL table, the syntax is as follows −

alter table yourTableName drop index `yourIndexName`;

Let us first create a table −

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)

Following is the query to add index on column name −

mysql> create index `Student Name_Index` on DemoTable1469(StudentName);
Query OK, 0 rows affected (0.33 sec)
Records: 0  Duplicates: 0  Warnings: 0

Let us check the table description −

mysql> desc DemoTable1469;

This will produce the following output −

+-------------+-------------+------+-----+---------+----------------+
| 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)

Following is the query to remove index −

mysql> alter table DemoTable1469 drop index `Student Name_Index`;
Query OK, 0 rows affected (0.23 sec)
Records: 0  Duplicates: 0  Warnings: 0

Let us check the table description once again −

mysql> desc DemoTable1469;

This will produce the following output −

+-------------+-------------+------+-----+---------+----------------+
| 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)