MySQL Learning summary----Index

MySQL Learning summary----Index

=================================================================================

First, the index

=================================================================================

=================================================================================

Ii. Creating and viewing indexes

=================================================================================

Creating and viewing indexes includes:

1) Create and view normal indexes

2) Create and view unique indexes

3) Create and view full-text indexes

4) Create and view multi-column indexes

A) Create and view normal indexes

Creating and viewing normal indexes is divided into:

1) Creating a table is to create a normal index

2) Create a normal index on a table that already exists

3) Create a normal index from the SQL statement ALTER TABLE

(i), creating a normal index when creating a table

CREATE TABLE Table name (

Property name Data type,

Property name Data type,

Property name Data type,

Index|key "Index Name" (Property name 1 "(length)" "Asc|desc")

);

Note: ASC indicates ascending, desc is descending; Index and key are used to create an index.

1. Create a table named Test in the database Doublelinux and add a normal index

Mysql> CREATE TABLE Test (

AAA int,

BBB varchar (20),

--CCC varchar (20),

-Index INDEX_AAA (AAA)

);

(ii) Create a normal index on a table that already exists

Create index index name on table name (property name "(length)" "Asc|desc")

1. Create an index named INDEX_CCC in table test01 under Database Doublelinux

Mysql> CREATE TABLE test01 (

zzz int,

-xxx varchar (20),

CCC int

);

Query OK, 0 rows affected (0.09 sec)

Mysql> CREATE index INDEX_CCC on test01 (CCC);

Query OK, 0 rows affected (0.11 sec)

records:0 duplicates:0 warnings:0

(iii),

II) Create and view unique indexes

III) Create and view full-text indexes

IV) Create and view multi-column indexes

=================================================================================

Third, delete the index

=================================================================================

This article from "Doublelinux" blog, declined reprint!

MySQL Learning summary----Index