MySQL index

MySQL创建和删除索引

创建普通索引：
alter table student add index index_dept(dept(8));

创建唯一索引
create unique index uni_ind_name on student (name);

根据列的前n个字符创建索引
create index index_dept on student(dept(8));

根据多个列创建联合索引
create index ind_name_dept on student(name,dept);

根据多个列的前n个字符创建联合索引
create index ind_name_dept on student (name(8), dept(10));

删除普通索引
alter table student drop index index_dept;
drop index index_dept on student;