create database mydb5;
use mydb5;
— –方式1-创建表的时候直接指定
create
table student(
sid int primary key,
card_id varchar(20),
name varchar(20),
gender varchar(20),
age int,
birth date,
phone_num varchar(20),
score double,
index index_name(name) — 给name列创建索引
);
select * from student where name = ‘张三’;
— –方式2-直接创建
— create index indexname on
tablename(columnname);
create index index_gender on
student(gender);
— –方式3-修改表结构(添加索引)
— alter table tablename add index
indexname(columnname)
alter table student add index
index_age(age);
—- 1、查看数据库所有索引
— select * from mysql.`innodb_index_stats`
a where a.`database_name` = ‘数据库名’;
select * from mysql.`innodb_index_stats` a
where a.`database_name` = ‘mydb5’;
—- 2、查看表中所有索引
— select * from mysql.`innodb_index_stats`
a where a.`database_name` = ‘数据库名’ and a.table_name
like ‘%表名%’;
select * from mysql.`innodb_index_stats` a
where a.`database_name` = ‘mydb5’ and a.table_name like ‘%student%’;
—- 3、查看表中所有索引
— show index from table_name;
show index from student;
—- 删除索引
/*
drop index 索引名 on 表名
— 或
alter table 表名 drop index 索引名
*/
drop
index index_gender on student;
alter table student drop index index_age;
— –索引的操作-创建索引-单列索引-唯一索引
/*
唯一索引与前面的普通索引类似，不同的就是：索引列的值必须唯一，但允许有空值。如果是组合索引，则列值的组合必须唯一。它有以下几种创建方式：
*/
— –方式1-创建表的时候直接指定
create
table student2(
sid int primary key,
card_id varchar(20),
name varchar(20),
gender varchar(20),
age int,
birth date,
phone_num varchar(20),
score double,
unique index_card_id(card_id) — 给card_id列创建索引
);
—- 方式2-直接创建
— create unique index 索引名 on 表名(列名)
create
table student2(
sid int primary key,
card_id varchar(20),
name varchar(20),
gender varchar(20),
age int,
birth date,
phone_num varchar(20),
score double
);
create unique index index_card_id on
student2(card_id);
— –方式3-修改表结构(添加索引)
— alter table 表名
add unique [索引名] (列名)
alter table student2 add unique
index_phone_num(phone_num);
— –操作-删除索引
drop
index index_card_id on student2;
alter table student2 drop index
index_phone_num;
—- 主键索引
show index from student2;
— –组合索引
use mydb5;
—- 创建索引的基本语法– 普通索引
create index indexname on
table_name(column1(length),column2(length));
create index index_phone_name on
student(phone_num,name);
— –操作-删除索引
drop
index index_phone_name on student;
—- 创建索引的基本语法– 唯一索引
create
unique index index_phone_name on student(phone_num,name);
select * from student where name = ‘张三’;
select * from student where phone_num =
‘15100046637’;
select * from student where phone_num =
‘15100046637’ and name = ‘张三’;
select * from student where name = ‘张三’ and phone_num = ‘15100046637’;
/*
三条sql只有 2 、 3、4能使用的到索引idx_phone_name,因为条件里面必须包含索引前面的字段 才能够进行匹配。
而3和4相比where条件的顺序不一样，为什么4可以用到索引呢？是因为mysql本身就有一层sql优化，他会根据sql来识别出来该用哪个索引，我们可以理解为3和4在mysql眼中是等价的。
*/
*/
show variables like ‘%ft%’;
use mydb5;
—- 创建表的适合添加全文索引
create table t_article (
id int primary key auto_increment ,
title varchar(255) ,
content varchar(1000) ,
writing_date date — ,
— fulltext (content) — 创建全文检索
);
insert into t_article
values(null,”Yesterday Once More”,”When I was young I listen to
the radio”,’2021-10-01′);
insert into t_article
values(null,”Right Here Waiting”,”Oceans apart, day after
day,and I slowly go insane”,’2021-10-02′);
insert into t_article values(null,”My
Heart Will Go On”,”every night in my dreams,i see you, i feel
you”,’2021-10-03′);
insert into t_article
values(null,”Everything I Do”,”eLook into my eyes,You will see
what you mean to me”,’2021-10-04′);
insert into t_article
values(null,”Called To Say I Love You”,”say love you no new
year’s day, to celebrate”,’2021-10-05′);
insert into t_article
values(null,”Nothing’s Gonna Change My Love For You”,”if i had
to live my life without you near me”,’2021-10-06′);
insert into t_article
values(null,”Everybody”,”We’re gonna bring the flavor show U
how.”,’2021-10-07′);
— –修改表结构添加全文索引
alter table t_article add fulltext
index_content(content)
— –添加全文索引
create fulltext index index_content on
t_article(content);
—- 使用全文索引
select * from t_article where
match(content) against(‘yo’); — 没有结果
select * from t_article where
match(content) against(‘you’); — 有结果
select * from t_article where content like
‘%you%’;
create table shop_info (
id int primary key auto_increment comment ‘id’,
shop_name varchar(64) not null comment ‘门店名称’,
geom_point
geometry not null comment ‘经纬度’,
spatial key geom_index(geom_point)
);
