【Linux】重生之从零开始学习运维之Mysql

Mysql基础指令

查看show

mysql

show databases;

use db1;
show tables;

创建create

show databases;
create database db2;
show databases;

use db2;
show tables;
create table test1 like db1.stu1;
desc test1;

修改alter

增add

alter table stu1 add phone varchar(11) after age;

删drop

alter table stu1 drop column phone;

改名rename

alter table stu1 rename stu;

修改字段名称和类型change

alter table stu change phone mobile char(10);

增加主键-primary key

alter table stu add primary key (id);

增加主键自增-auto_increment

alter table stu modify column id int unsigned not null auto_increment;

自增起始值

alter table stu auto_increment=1;

插入数据

insert stu (name,age) values ('zhangsan',15);

移除drop

删除表

drop table user3;

DML语句-insert、update、delete

插入数据

插入单行数据-insert

insert stu (name,age) values('xiaoming',20);

insert stu (name,age,is_del) values('xiaohong',18,false);

插入单行数据-insert into

insert into stu values(12,'xiaoli',11111111112,19,null);

插入多行数据

insert into xxx values(,),(,)...;

insert into stu (name,age) values('test1',20),('test2',21),('test3',22);

以更新的方式插入数据

insert into xxxx values() on duplicate key update xxx='xxx';

insert into stu (id,name) values(12,'zhangsan') on duplicate key update name='zhangsan';

将查询结果当值插入

insert into stu (name,age) select name,age from stu where id=11;

更新数据

根据条件更新数据-update

update stu set age=26 where id>12;

多个条件or、and

update stu set age=21 where (id=15 or name is null);

update stu set age=22 where (id=16 and name='xiaohong');

删除数据

根据条件删除-delete

delete from stu where id=16;

指定多条件删除

delete from stu where (mobile is null and id=15);

清空表数据

清空表

truncate table xxx
delete from xxx

DQL 语句

查询-select

普通查询

select * from stu;

AS方式将标题改名

select id as 学号,name as 姓名,age as 姓名 from stu;

多条件查询

select id,name from stu where id>15;

select id,name,age from stu where id in (10,14,15,17);

排序

指定排序order by

select * from stu order by name;

去重distinct

select distinct(age) from stu order by age desc;

Mysql视图基础

view视图

创建view视图

create view xxx as xxxxx;

create view v_stu as select * from stu where age=18;

更新视图信息

update v_stu set age=20 where id=16;

删除view视图

drop view v_stu;