创建索引
创建数据表时创建索引
create table tablename(
…
[unique|fulltext|spatial] index/key
[别名] (col [(length)][asc|desc])
);
unique 唯一性索引
fulltext 全文索引
asc 升序
desc 降序
在已存在的数据表中创建索引
create [unique|fulltext|spatial] index indexname
on tablename (row [(length)] [asc|desc]);
修改数据表结构添加索引
alter table tablename add [unique|fulltext|spatial] index indexname(row [(length)] [asc|desc]);
删除索引
drop index indexname on tablename;