mysql添加索引

1.添加PRIMARY KEY（主键索引） 

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

 

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

 

3.添加INDEX(普通索引) 

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

 

4.添加FULLTEXT(全文索引) 

mysql>ALTER TABLE  table_name  ADD FULLTEXT ( column) ;

 

5.添加多列索引 
mysql>ALTER TABLE  tabname ADD INDEX index_name ( column1, column2, column3 );

show  index from tablename;
alter table tbname  drop index index_name;