Can indexes be deleted in mysql?-Mysql Tutorial-php.cn

Indexes in mysql can be deleted. You can use the "DROP INDEX" statement to delete the index. The syntax format is "DROP INDEX ON " . It is recommended to delete unused indexes because they will slow down the update speed of the table and affect the performance of the database.

Can indexes be deleted in mysql?

(Recommended tutorial: mysql video tutorial)

Deleting an index means to delete the table Delete existing indexes. It is recommended to delete unused indexes because they will slow down the update speed of the table and affect the performance of the database. For such an index, it should be deleted.

Basic syntax

When the index is no longer needed, you can use the DROP INDEX statement to delete the index.

Grammar format:

DROP INDEX <索引名> ON <表名>

Copy after login

The syntax description is as follows:

: The name of the index to be deleted.

: Specify the table name where the index is located.

Example:

Delete the index in the table tb_stu_info. The input SQL statement and execution results are as follows.

mysql> DROP INDEX height
    -> ON tb_stu_info;
Query OK, 0 rows affected (0.27 sec)
Records: 0  Duplicates: 0  Warnings: 0
mysql> SHOW CREATE TABLE tb_stu_info\G
*************************** 1. row ***************************
       Table: tb_stu_info
Create Table: CREATE TABLE `tb_stu_info` (
  `id` int(11) NOT NULL,
  `name` char(45) DEFAULT NULL,
  `dept_id` int(11) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  `height` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=gb2312
1 row in set (0.00 sec

Copy after login

The above is the detailed content of Can indexes be deleted in mysql?. For more information, please follow other related articles on the PHP Chinese website!

Related labels：

mysql index

source：php.cn

Previous article：How to delete mysql57 service Next article：How to upgrade mysql to 5.7

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn