参考博客：https://www.cnblogs.com/guochaoxxl/p/14038413.html
参考博客：https://www.cnblogs.com/guochaoxxl/p/14028827.html
一、创建普通数据库用户并添加权限
创建一个普通用户可以通过以下三种方法
方法一：
MariaDB [(none)]>create user newuser@localhost identified by '1234‘//newuser为用户名，’1234‘为密码
MariaDB [(none)]> select user from mysql.user;方法二：
MariaDB [(none)]>insert into mysql.user(user,host,password) values('newuser','localhost',password('1234'));MariaDB [(none)]> flush privileges;//刷新系统权限表这两种方法直接创建了用户，但没有给他们权限，无法进行创建表。只需给对应账户，赋予所有的权限即可：
可通过以下方法给予权限
mysql>grant all privileges on xxx_info.* to newuser; //xxx_info是数据库，newuser是操纵xxx_info的用户
mysql>flush privileges; //刷新系统权限表
或直接在终端添加权限
mysql -u root -p -e "GRANT SELECT ON *.* TO 'newuserl'@'localhost';"//使用命令赋予用户select权限：
mysql -u root -p -e "GRANT ALL ON *.* TO 'sqlxxl'@'localhost';"//使用命令赋予用户所有权限：
方法三：直接创建普通用户并基于权限
mysql -u root -p -e "GRANT USAGE ON *.* to 'newuser'@'localhost' identified by '1234';" //mysql -u root -p：sql使用root登陆 //-e：执行后面的命令 //GRANT USAGE ON *.*：赋予所有权限 //to 'newuser'@'localhost' ：标识本地用户名称为newuser //identified by '1234';"：用户密码为1234
二、登陆mysql账号进行建表
mysql -unewuser -p
/*如果之前退出了数据库，需要使用命令systemctl start mariadb 来开启mysql服务，
否则回出现错误ERROR 2002 (HY000): Can't connect to local MySQL server throug
h socket '/run/mysqld/mysqld.sock' (2)*/
输入密码后可进入账号进而操作
MariaDB [(none)]> show databases;//查看数据库 +--------------------+ | Database | +--------------------+ | Public_bus_info | | birdWatchers | | book_dinner_info | | information_schema | | mysql | | performance_schema | | rookery | | student_info | +--------------------+ 8 rows in set (0.001 sec) MariaDB [(none)]> create database menu;//创建数据库menu Query OK, 1 row affected (0.001 sec) MariaDB [(none)]> show databases; +--------------------+ | Database | +--------------------+ | Public_bus_info | | birdWatchers | | book_dinner_info | | information_schema | | menu | | mysql | | performance_schema | | rookery | | student_info | +--------------------+ 9 rows in set (0.001 sec)
MariaDB [student_info]> drop database menu; //删除数据库
Query OK, 0 rows affected (0.007 sec)
MariaDB [student_info]> show databases;
+--------------------+
| Database |
+--------------------+
| Public_bus_info |
| birdWatchers |
| book_dinner_info |
| information_schema |
| mysql |
| performance_schema |
| rookery |
| student_info |
+--------------------+
8 rows in set (0.001 sec)
MariaDB [student_info]> use student_info; //应用数据库
Database changed
数据库的基本操作
SELECT - 从数据库表中获取数据 UPDATE - 更新数据库表中的数据 DELETE - 从数据库表中删除数据 INSERT INTO - 向数据库表中插入数据 CREATE DATABASE - 创建新数据库 ALTER DATABASE - 修改数据库 CREATE TABLE - 创建新表 ALTER TABLE - 变更（改变）数据库表 DROP TABLE - 删除表 CREATE INDEX - 创建索引（搜索键） DROP INDEX - 删除索引
MariaDB [student_info]> show tables;//查看数据库中的表 Empty set (0.001 sec)
MariaDB [student_info]> create table stu_info(id INT, name TEX
T, age INT); //创建表stu_info
Query OK, 0 rows affected (0.013 sec)
MariaDB [student_info]> show tables;//查看数据库中的表
+------------------------+
| Tables_in_student_info |
+------------------------+
| stu_info |
+------------------------+
1 row in set (0.001 sec)
MariaDB [student_info]> describe stu_info;//查看表中的详细结构
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id | int(11) | YES | | NULL | |
| name | text | YES | | NULL | |
| age | int(11) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
3 rows in set (0.001 sec)
MariaDB [student_info]> insert into stu_info values(22, "zhang
san", 11); //向表中插入数据
Query OK, 1 row affected (0.007 sec)
MariaDB [student_info]> insert into stu_info values(22, "zhang
san", 11);
Query OK, 1 row affected (0.007 sec)
MariaDB [student_info]> select * from stu_info; //查询表的内容
+------+----------+------+
| id | name | age |
+------+----------+------+
| 22 | zhangsan | 11 |
| 22 | zhangsan | 11 |
+------+----------+------+
2 rows in set (0.000 sec)
MariaDB [student_info]> select * from stu_info where age = 11\
G;//查询表，改变显示方式
*************************** 1. row ***************************
id: 22
name: zhangsan
age: 11
*************************** 2. row ***************************
id: 22
name: zhangsan
age: 11
2 rows in set (0.006 sec)
ERROR: No query specified
MariaDB [student_info]> update stu_info set age = 11 where id
= 22;//更新表信息
Query OK, 0 rows affected (0.006 sec)
Rows matched: 2 Changed: 0 Warnings: 0
MariaDB [student_info]> select * from stu_info where age = 11; //条件查询表的内容
+------+----------+------+
| id | name | age |
+------+----------+------+
| 22 | zhangsan | 11 |
| 22 | zhangsan | 11 |
+------+----------+------+
2 rows in set (0.001 sec)