Add an index to a field in MySQL

1 General Index

ALTER TABLE ADD INDEX index_name ('column')

2 PRIMARY Key index

ALTER TABLE ADD PRIMARY KEY ('column

3 Unique Indexes

ALTER TABLE ADD UNIQUE ('column

A unique index here guarantees uniqueness of the data record, and in many cases, creating a unique index is not intended to speed up access, but to limit the uniqueness of the data.

4 Full-Text indexing

ALTER TABLE ADD Fulltext ('column

Introduction to Full-text indexing

5 Multi-column index

ALTER TABLE ADD INDEX index_name (' column1 ', ' column2 ', ' column3 ')

Reference articles

Add an index to a field in MySQL