yum -y install httpd mariadb-server mariadb php php-mysql
[root@xuegod63 ~]# systemctl start mariadb
[root@xuegod63 ~]# mysql_secure_installation
[root@xuegod63 ~]# vim /etc/php.ini #php运用程序的配置文件
改:211 short_open_tag = Off
为:211 short_open_tag = On
show databases; use mysql; show tables; select database();#查看所处的位置 mysql -e 'show databases' -uroot -p123456 select now(),user(),database();
删库
MariaDB [xuegod]> drop database `HA-test`; 直接到数据库存放目录移出就行 MariaDB [HA]> create database `HA-test1`; [root@xuegod63 mysql]# mv /var/lib/mysql/HA@002dtest1 /opt/ show databases; drop database if exists `HA-test`; #IF EXISTS:若是存在
建立表:
MariaDB [xuegod]> create database xuegod; MariaDB [xuegod]> use xuegod; MariaDB [xuegod]> create table student(id int(20),name char(40),age int);
查看表结构
MariaDB [xuegod]> desc student;
(4)查看建立表执行了哪些命令:
MariaDB [xuegod]> show create table student \G MariaDB [xuegod]> create table student2(id int(20),name char(40),age int)ENGINE=MyISAM DEFAULT CHARSET=utf8;
#能够指定表的默认存储引擎和字符集
alter table student rename students; #修改表名 alter table students modify id int(10);#修改字段类型 alter table students change name stname char(20);#修更名字和字段 alter table students add sex enum('M','W');#添加字段 alter table students add uid int(10) first;#添加到第一列 alter table students add address char(40) after age;#添加到age字段后面 alter table students drop address; #删除某address字段
create table student(id int(20),name char(40),age int); insert into student values(2,'lis',24),(3,'wange',26); select * from student; select * from student\G #字段按行显示 select *from HA.student;#跨库查询 delete from students where id=3;#删除数据 delete from students where age is null; 删除adge为空的内容 update students set sex='M' where id=2;更新 select distinct name,age from student;#去重查询 select id,name,age from student where id>3 and age>25;#多条件查询 select * from students where stname='zhangsan' and (age=21 or age=24); select * from student where binary name='jk';#区分大小写查询 默认不区分 select distinct id from student order by id asc;#升序 select distinct id from student order by id desc;#降序 help show;
mysqldump -uroot -p123456 -B 迁移的库名 > 导出名称.sql
yum 安装mysql5.7的方法:
yum -y remove mariadb* rpm -Uvh https://repo.mysql.com//yum/mysql-5.7-community/el/7/x86_64/mysql57-community-release-el7-10.noarch.rpm yum list #刷新yum源缓存 yum -y install mysql-community-server #安装mysql5.7 systemctl start mysqld #启动mysql会生成临时密码 grep "password" /var/log/mysqld.log 命令获取MySQL的临时密码 mysql -uroot -p'&B=o4Fp!Rq_X'
方法一:首先,修改validate_password_policy参数的值
MariaDB [xuegod]> set global validate_password_policy=0; #定义复杂度 MariaDB [xuegod]> set global validate_password_length=1; #定义长度 默认是8 MariaDB [xuegod]> set password for 'root'@'localhost'=password('123456'); MariaDB [xuegod]> flush privileges;
方法二:在/etc/my.cnf 可关闭密码强度审计插件,重启mysql服务
validate-password=ON/OFF/FORCE/FORCE_PLUS_PERMANENT#(及强制/永久强制使用)。
mysql -uroot -p123456 < 导出名称.sql
字符集的查询和修改
show variables like 'character_set%';#当前字符集 show create table user \G #查看表的字符集 SHOW CREATE DATABASE mysql;#查看库的字符集 SHOW FULL COLUMNS FROM user;#查看字段编码 ALTER DATABASE db_name DEFAULT CHARACTER SET character_name [COLLATE ...]; ALTER TABLE logtest DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci; ALTER TABLE logtest CHANGE title title VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci; select * from user\G
数据库导入导出
mysqldump -uroot -p123456 -A >all.sql mysqldump -uroot -p123456 --all-databases >all2.sql A:导入全部数据库 mysql -uroot -p123456 <all.sql
强制修改密码5.7 mysql
5.7 版本强制修改密码 vi /etc/my.cnf [mysqld] skip-grant-tables
执行修改命令 5.7之前用 update user set authentication_string=password('123456') where User='root';update usersetpassword=password(“新密码”) where user=”用户名”;
没法建表sbtest1s删除表空间就能够了
[root@mysql115 ~]# ll /var/lib/mysql/pcms 总用量 36 -rw-r----- 1 mysql mysql 61 8月 17 09:02 db.opt -rw-r----- 1 mysql mysql 65536 8月 17 09:09 sbtest1.ibd [root@mysql115 ~]# rm /var/lib/mysql/pcms/sbtest1.ibd rm:是否删除普通文件 "/var/lib/mysql/pcms/sbtest1.ibd"?y