mysql Add and Remove Uniqueness Index of unique for Fields

1. Add PRIMARY KEY (primary key index)

mysql > ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )

2. Add UNIQUE (only 1 index)

mysql > ALTER TABLE `table_name` ADD UNIQUE ( `column` )

3. Add INDEX (common index)

mysql > ALTER TABLE `table_name` ADD INDEX index_name ( `column` )

4. Add FULLTEXT (full-text index)

mysql > ALTER TABLE `table_name` ADD FULLTEXT ( `column`)

5. Add a multi-column index

mysql > ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )