MySQL的索引创建、删除

1_1.添加PRIMARY KEY（主键索引） 

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

1_2.添加UNIQUE(唯一索引) 
mysql>ALTER TABLE `table_name` ADD UNIQUE ( `column` ) 

1_3.添加INDEX(普通索引) 

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

1_4.添加FULLTEXT(全文索引) 

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

1_5.添加多列索引 
mysql>ALTER TABLE `table_name` ADD INDEX your_index_name ( `column1`, `column2`, `column3` )

2_1.删除索引

mysql>drop index your_index_name on table_name ;