mysql基础
目录
- mysql基础
- mysql安装
- 虚拟格式化
- mysql工具使用
- 数据库操作
- 表操作
- 用户操作
- 查看命令SHOW
- 获取帮助
- MySQL 数据类型
mysql安装
第一种方式：使用yum进行安装
第二种方式：yum安装mariadb
yum install -y mariadb*
配置mysql的yum源:
[root@lnh ~]# wget http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
--2022-07-25 17:03:13-- http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
Resolving dev.mysql.com (dev.mysql.com)... 184.29.181.90, 2600:1402:b800:1194::2e31, 2600:1402:b800:118f::2e31
Connecting to dev.mysql.com (dev.mysql.com)|184.29.181.90|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm [following]
--2022-07-25 17:03:13-- https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
Connecting to dev.mysql.com (dev.mysql.com)|184.29.181.90|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm [following]
--2022-07-25 17:03:14-- https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
Resolving repo.mysql.com (repo.mysql.com)... 184.30.152.230
Connecting to repo.mysql.com (repo.mysql.com)|184.30.152.230|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25680 (25K) [application/x-redhat-package-manager]
Saving to: ‘mysql57-community-release-el7-11.noarch.rpm’
mysql57-community- 100%[================>] 25.08K 125KB/s in 0.2s
2022-07-25 17:03:15 (125 KB/s) - ‘mysql57-community-release-el7-11.noarch.rpm’ saved [25680/25680]
[root@lnh ~]# rpm -Uvh mysql57-community-release-el7-11.noarch.rpm
warning: mysql57-community-release-el7-11.noarch.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Verifying... ################################# [100%]
Preparing... ################################# [100%]
Updating / installing...
1:mysql57-community-release-el7-11 ################################# [100%]
[root@lnh ~]# rpm -Uvh mysql57-community-release-el7-11.noarch.rpm
warning: mysql57-community-release-el7-11.noarch.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Verifying... ################################# [100%]
Preparing... ################################# [100%]
Updating / installing...
1:mysql57-community-release-el7-11 ################################# [100%]
[root@lnh ~]# dnf module disable mysql //禁用mysql
MySQL Connectors Community 47 kB/s | 49 kB 00:01
MySQL Tools Community 257 kB/s | 651 kB 00:02
MySQL 5.7 Community Server 817 kB/s | 2.6 MB 00:03
Dependencies resolved.
============================================================================
Package Architecture Version Repository Size
============================================================================
Disabling modules:
mysql
Transaction Summary
============================================================================
Is this ok [y/N]: y
Complete!
[root@lnh ~]# dnf -y install mysql-community-server mysql-community-client mysql-community-common mysql-community-devel --nogpgcheck //不验证合法性进行下载
[root@lnh ~]# systemctl enable --now mysqld //设置开机自启
[root@lnh ~]# systemctl status mysqld.service //查看状态
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor >
Active: active (running) since Mon 2022-07-25 17:36:19 CST; 12s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 67864 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run>
Process: 67814 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, sta>
Main PID: 67866 (mysqld)
Tasks: 27 (limit: 12221)
Memory: 310.2M
CGroup: /system.slice/mysqld.service
└─67866 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/>
Jul 25 17:36:17 lnh systemd[1]: Starting MySQL Server...
Jul 25 17:36:19 lnh systemd[1]: Started MySQL Server.
[root@lnh ~]# ss -antl //查看3306端口是否出现
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 128 *:80 *:*
LISTEN 0 128 [::]:22 [::]:*
LISTEN 0 80 *:3306 *:*
[root@lnh ~]# grep "password" /var/log/mysqld.log
2022-07-25T09:36:17.891633Z 1 [Note] A temporary password is generated for root@localhost: eNGwhYkrz3_(
//在日志文件中找出临时密码
[root@lnh ~]# mysql -uroot -p //使用临时密码登录
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.38
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
//修改mysql登录密码
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'xbz123';
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@lnh ~]# mysql -uroot -pxbz123 //验证密码修改成功
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
[root@lnh ~]# rpm -qa |grep mysql
mysql-community-client-5.7.38-1.el7.x86_64
mysql57-community-release-el7-11.noarch
mysql-community-common-5.7.38-1.el7.x86_64
mysql-community-server-5.7.38-1.el7.x86_64
mysql-community-devel-5.7.38-1.el7.x86_64
mysql-community-libs-5.7.38-1.el7.x86_64
[root@lnh ~]# rpm -e mysql57-community-release-el7-11.noarch
//卸载这个包防止其更新
虚拟格式化
[root@lnh ~]# mysql_secure_installation
Securing the MySQL server deployment.
Enter password for user root: //之前的密码
The 'validate_password' plugin is installed on the server.
The subsequent steps will run with the existing configuration
of the plugin.
Using existing password for root.
Estimated strength of the password: 50
Change the password for root ? ((Press y|Y for Yes, any other key for No) : y
New password: //新密码
Re-enter new password: //再次输入
Estimated strength of the password: 50
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.
Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.
Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : n
//不让ssh远程连接数据库
... skipping.
By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
- Dropping test database...
Success.
- Removing privileges on test database...
Success.
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.
All done!
mysql工具使用
[root@lnh ~]# mysql -V
mysql Ver 14.14 Distrib 5.7.38, for Linux (x86_64) using EditLine wrapper
//查看当前版本
[root@lnh ~]# mysql -uroot -pxbz123 -h127.0.0.1
//-h 指定服务器主机，默认为localhost，推荐使用ip地址
//直接在命令行输入密码登录
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> quit
Bye
[root@lnh ~]# mysql -uroot -p -h127.0.0.1
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
//注意，不推荐直接在命令行里直接用-pPASSWORD的方式登录，而是使用-p选项，然后交互式输入密码
[root@lnh ~]# mysql -uroot -p -h127.0.0.1 -e 'SHOW DATABASES;'
Enter password:
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
//不登录mysql查看有哪些数据库
数据库操作
mysql> create database tushanbu;
Query OK, 1 row affected (0.00 sec)
//创建数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| tushanbu |
+--------------------+
5 rows in set (0.00 sec)
//查看数据库
mysql> drop database tushanbu
-> ;
Query OK, 0 rows affected (0.01 sec)
//删除数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
//查看数据库
表操作
mysql> create database tushanbu;
Query OK, 1 row affected (0.00 sec)
//创建数据库
mysql> use tushanbu; //进入数据库
Database changed
mysql> create table tsb(id int not null,name varchar(100) not null,age int);
Query OK, 0 rows affected (0.02 sec)
//创建表
mysql> desc tsb; //查看结构
+-------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id | int(11) | NO | | NULL | |
| name | varchar(100) | NO | | NULL | |
| age | int(11) | YES | | NULL | |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.01 sec)
mysql> show tables;
+--------------------+
| Tables_in_tushanbu |
+--------------------+
| tsb |
+--------------------+
1 row in set (0.00 sec)
//查看表
mysql> drop table tsb;
Query OK, 0 rows affected (0.01 sec)
//删除表
mysql> show tables;
Empty set (0.00 sec)
//查看
用户操作
mysql> create user 'lnh'@'127.0.0.1' identified by 'xbz123';
Query OK, 0 rows affected (0.01 sec)
//创建数据库用户lnh
mysql> quit
Bye
[root@lnh ~]# mysql -ulnh -pxbz123 -h127.0.0.1 //使用新创建的用户和密码登录
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
[root@lnh ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> drop user 'lnh'@'127.0.0.1'; //删除数据库用户
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@lnh ~]# mysql -ulnh -pxbz123 -h127.0.0.1
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'lnh'@'localhost' (using password: YES
//已经删除
查看命令SHOW
[root@lnh ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show character set; //查看支持的所有字符集
+----------+---------------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
...
mysql> show engines; //查看当前数据库支持的所有存储引擎
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)
mysql> show databases; //查看数据库的信息
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| tushanbu |
+--------------------+
5 rows in set (0.00 sec)
mysql> show tables from tushanbu; //不进去其数据库查看表
+--------------------+
| Tables_in_tushanbu |
+--------------------+
| tsb |
+--------------------+
1 row in set (0.00 sec)
mysql> desc tushanbu.tsb; //不进入数据库查看数据库表的结构
+-------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id | int(11) | NO | | NULL | |
| name | varchar(100) | NO | | NULL | |
| age | int(11) | YES | | NULL | |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
mysql> show create table tushanbu.tsb; //创建某表的创建命令
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| tsb | CREATE TABLE `tsb` (
`id` int(11) NOT NULL,
`name` varchar(100) NOT NULL,
`age` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> use tushanbu;
mysql> show table status like 'tsb'\G
*************************** 1. row ***************************
Name: tsb
Engine: InnoDB
Version: 10
Row_format: Dynamic
Rows: 0
Avg_row_length: 0
Data_length: 16384
Max_data_length: 0
Index_length: 0
Data_free: 0
Auto_increment: NULL
Create_time: 2022-07-25 22:12:10
Update_time: NULL
Check_time: NULL
Collation: latin1_swedish_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)
//进入数据库查看表的状态
获取帮助
mysql> help create table;
Name: 'CREATE TABLE'
Description:
Syntax:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
(create_definition,...)
[table_options]
[partition_options]
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
[(create_definition,...)]
[table_options]
[partition_options]
[IGNORE | REPLACE]
[AS] query_expression
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
{ LIKE old_tbl_name | (LIKE old_tbl_name) }
create_definition: {
col_name column_definition
| {INDEX | KEY} [index_name] [index_type] (key_part,...)
[index_option] ...
| {FULLTEXT | SPATIAL} [INDEX | KEY] [index_name] (key_part,...)
[index_option] ...
| [CONSTRAINT [symbol]] PRIMARY KEY
[index_type] (key_part,...)
//获取创建表的帮助
MySQL 数据类型
MySQL中定义数据字段的类型对数据库的优化是非常重要的。MySQL支持多种类型，大致可以分为三类：数值、日期/时间和字符串(字符)类型。
数值类型
MySQL支持所有标准SQL数值数据类型。这些类型包括严格数值数据类型(INTEGER、SMALLINT、DECIMAL和NUMERIC)，以及近似数值数据类型(FLOAT、REAL和DOUBLE PRECISION)。
关键字INT是INTEGER的同义词，关键字DEC是DECIMAL的同义词。BIT数据类型保存位字段值，并且支持MyISAM、MEMORY、InnoDB和BDB表。作为SQL标准的扩展，MySQL也支持整数类型TINYINT、MEDIUMINT和BIGINT。下面的表显示了需要的每个整数类型的存储和范围
注意：char(n) 和 varchar(n) 中括号中 n 代表字符的个数，并不代表字节个数，比如 CHAR(30) 就可以存储 30 个字符。
CHAR 和 VARCHAR 类型类似，但它们保存和检索的方式不同。它们的最大长度和是否尾部空格被保留等方面也不同。在存储或检索过程中不进行大小写转换。
BINARY 和 VARBINARY 类似于 CHAR 和 VARCHAR，不同的是它们包含二进制字符串而不要非二进制字符串。也就是说，它们包含字节字符串而不是字符字符串。这说明它们没有字符集，并且排序和比较基于列值字节的数值值。
BLOB 是一个二进制大对象，可以容纳可变数量的数据。有 4 种 BLOB 类型：TINYBLOB、BLOB、MEDIUMBLOB 和 LONGBLOB。它们区别在于可容纳存储范围不同。
有 4 种 TEXT 类型：TINYTEXT、TEXT、MEDIUMTEXT 和 LONGTEXT。对应的这 4 种 BLOB 类型，可存储的最大长度不同，可根据实际情况选择。
来源：原文
Category: Linux