Skip to content

mysql命令

mysql命令

image-20240418064318970

目录

[toc]

容器起docker

案例:docker容器起mysql

bash
$ docker run --rm -it --platform=linux/amd64 --network mysql_default mysql:5.7 mysql -h proxy -P 1999 -u root --skip-ssl
# ......
mysql> CREATE DATABASE test;
Query OK, 1 row affected (0.00 sec)

mysql> USE test;
Database changed
mysql> CREATE TABLE test ( text VARCHAR(255) );
Query OK, 0 rows affected (0.01 sec)

mysql> SELECT COUNT(*) FROM test;
+----------+
| COUNT(*) |
+----------+
|        0 |
+----------+
1 row in set (0.01 sec)

mysql> INSERT INTO test VALUES ('hello, world!');
Query OK, 1 row affected (0.00 sec)

mysql> SELECT COUNT(*) FROM test;
+----------+
| COUNT(*) |
+----------+
|        1 |
+----------+
1 row in set (0.00 sec)

mysql> exit
Bye

案例:docker-compose起mysql:5.7

docker-compose.yaml

yaml
version: '3'

services:
  piwigo:
    image: lscr.io/linuxserver/piwigo:latest
    container_name: piwigo
    ports:
      - "8080:80" # 端口映射,官方默认80端口,前面可自己修改成VPS未被占用端口
    depends_on:
      - db
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Asia/Shanghai # 时区,中国时区为Asia/Shanghai
    volumes:
      - ./config:/config
      - ./gallery:/gallery

  db:
    image: mysql:5.7
    container_name: mysql_piwigo
    environment:
      MYSQL_ROOT_PASSWORD: SSbw5pK_bSDvqIXIEeDHPg # root用户密码
      MYSQL_DATABASE: piwigo # 数据库名
      MYSQL_USER: piwigo # 用户名
      MYSQL_PASSWORD: xO4G-U28etWMNWoyx9OtFg # piwigo用户数据库密码
    volumes:
      - ./mysql_data:/var/lib/mysql 

volumes:
  mysql_data:
  config:
  gallery:
  • 运行项目
bash
cd /root/piwigo
docker-compose pull
docker-compose up -d

#查看
[root@docusaurus-wiki piwigo]#docker-compose ps
NAME           IMAGE                               COMMAND                  SERVICE   CREATED          STATUS          PORTS
mysql_piwigo   mysql:5.7                           "docker-entrypoint.s…"   db        12 minutes ago   Up 12 minutes   3306/tcp, 33060/tcp
piwigo         lscr.io/linuxserver/piwigo:latest   "/init"                  piwigo    12 minutes ago   Up 12 minutes   443/tcp, 0.0.0.0:8080->80/tcp
[root@docusaurus-wiki piwigo]#

k8s里部署mysql

yaml
# mysql.yaml
apiVersion: v1
kind: Service
metadata:
  name: mysql
  namespace: kube-example
  labels:
    app: mysql
spec:
  ports:
    - port: 3306
      targetPort: dbport
  selector:
    app: mysql
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: kube-example
  labels:
    app: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:   
      containers:
        - name: mysql
          image: mysql:5.7
          imagePullPolicy: IfNotPresent
          args: # 新版本镜像有更新,需要使用下面的认证插件环境变量配置才会生效
            - --default_authentication_plugin=mysql_native_password
            - --character-set-server=utf8mb4
            - --collation-server=utf8mb4_unicode_ci
          ports:
            - containerPort: 3306
              name: dbport
          volumeMounts:
          - name: mysql-data
            mountPath: /var/lib/mysql
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: rootPassW0rd
            - name: MYSQL_DATABASE
              value: wordpress
            - name: MYSQL_USER
              value: wordpress
            - name: MYSQL_PASSWORD
              value: wordpress

  volumeClaimTemplates:
      - metadata:
          name: mysql-data
        spec:
          accessModes: ["ReadWriteOnce"]
          storageClassName: nfs-client
          resources:
            requests:
              storage: 1Gi

image-20240309171239036

wordpress.yaml

yaml
# wordpress.yaml
apiVersion: v1
kind: Service
metadata:
  name: wordpress
  namespace: kube-example
  labels:
    app: wordpress
spec:
  selector:
    app: wordpress
  type: NodePort
  ports:
    - name: web
      port: 80
      targetPort: wdport
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress
  namespace: kube-example
  labels:
    app: wordpress
spec:
  replicas: 2
  selector:
    matchLabels:
      app: wordpress
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0      
  template:
    metadata:
      labels:
        app: wordpress
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution: # 软策略
            - weight: 1
              podAffinityTerm:
                topologyKey: kubernetes.io/hostname
                labelSelector:
                  matchExpressions:
                    - key: app
                      operator: In
                      values:
                        - wordpress         
      containers:
        - name: wordpress
          image: wordpress:6.4.3-apache
          ports:
            - containerPort: 80
              name: wdport
          readinessProbe:
            tcpSocket:
              port: 80
            initialDelaySeconds: 5
            periodSeconds: 5 
          lifecycle:
            preStop:
              exec:
                command: ["/bin/bash", "-c", "sleep 20"]                         
          resources:
            limits:
              cpu: 150m
              memory: 150Mi
            requests:
              cpu: 150m
              memory: 150Mi 
          volumeMounts:
          - name: wordpress-data
            mountPath: /var/www/html         
          env:
            - name: WORDPRESS_DB_HOST
              value: mysql:3306
            - name: WORDPRESS_DB_USER
              value: wordpress
            - name: WORDPRESS_DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: wordpress-db-pwd
                  key: dbpwd              
      volumes:
      - name: wordpress-data
        persistentVolumeClaim:
          claimName: wordpress-pvc
---
# pdb.yaml
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: wordpress-pdb
  namespace: kube-example
spec:
  maxUnavailable: 1
  selector:
    matchLabels:
      app: wordpress

image-20240309171437788

mysql常用命令

命令汇总

sql
mysql -uroot -ppassword #登录数据库

show databases; #查看数据库

#创建数据库
CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME'
CHARACTER SET 'character set name'
COLLATE 'collate name';
或者
CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME';
或者
CREATE DATABASE|SCHEMA 'DB_NAME';

#查看创建的数据库字符集
show create database db1;
#查看当前告警;
show warnings;

#修改数据库的字符集
ALTER DATABASE DB_NAME character set utf8;

mysql  test #直接指定对应数据库
use mysql; #进入数据库
	show tables; #显示当前数据库的表列表:
	
	#查看表内容
	select *from t1;
	等价于
	select * from t1;
	
	#查看用户名和密码
	select Host,User,Password from user; #查看数据库user表
	==等价于
	SELECT User,Host,Password FROM user; ##注意:关键字这里的大小写都是可以的哦;
	==等价于
	select user,host,password from user;
	
	#select user,host,password,authentication_string from user; #密码可能存放在这2个字段,和数据版本有关;
	
	desc user; #查看某张表所有列的内容
	
	#查看当前用户
	\s
	或者
	select User();
	
	#加载授权表:立即生效的。
	
	SHOW CHARACTER SET; #查看支持所有的字符集
	show variables like 'character%'; #查看当前字符集的使用情况
	
	show COLLATION; #查看支持所有排序规则
	SHOW VARIABLES LIKE 'collation%'; #查看当前使用的排序规则
	
	SELECT VERSION(); #查看当前mysql版本
	或者
	\s #也行的
	mysqld --version
	
	#查看当前连接数据库的端口
	show variables like 'PORT';
	或者
	show variables like 'port';

#删除数据库
DROP DATABASE|SCHEMA [IF EXISTS] 'DB_NAME';

\q #退出数据库 ==exit

#导入sql数据
mysql < hellodb_innodb.sql

show processlist; #查看mysql线程

登录数据库、查看当前数据库数量

bash
#进入pod测试mysql应用
mysql -uroot -ppassword #登录数据库
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 1
Server version: 5.6.51 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights reserved.

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 databases;
+---------------------+
| Database            |
+---------------------+
| information_schema  |
| #mysql50#lost+found |
| mysql               |
| performance_schema  |
+---------------------+
4 rows in set (0.05 sec)

mysql> create database longhorn;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+---------------------+
| Database            |
+---------------------+
| information_schema  |
| longhorn            |
| #mysql50#lost+found |
| mysql               |
| performance_schema  |
+---------------------+
5 rows in set (0.00 sec)

mysql> exit
Bye
[root@master1 ~]#

使用某个数据库

bash
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
+--------------------+
3 rows in set (0.01 sec)

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql>

显示当前数据库的表列表

bash
MariaDB [mysql]> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| column_stats              |
| columns_priv              |
| db                        |
| event                     |
| func                      |
| general_log               |
| global_priv               |
| gtid_slave_pos            |
| help_category             |
| help_keyword              |
| help_relation             |
| help_topic                |
| index_stats               |
| innodb_index_stats        |
| innodb_table_stats        |
| plugin                    |
| proc                      |
| procs_priv                |
| proxies_priv              |
| roles_mapping             |
| servers                   |
| slow_log                  |
| table_stats               |
| tables_priv               |
| time_zone                 |
| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| transaction_registry      |
| user                      |
+---------------------------+
31 rows in set (0.001 sec)

MariaDB [mysql]>

查看数据库user表

bash
mysql> select Host,User,Password from user;
+-----------+------+-------------------------------------------+
| Host      | User | Password                                  |
+-----------+------+-------------------------------------------+
| localhost | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| 127.0.0.1 | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| ::1       | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
+-----------+------+-------------------------------------------+
3 rows in set (0.00 sec)

mysql> 

mysql> SELECT User,Host,Password FROM user;
+------+-----------+-------------------------------------------+
| User | Host      | Password                                  |
+------+-----------+-------------------------------------------+
| root | localhost | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| root | 127.0.0.1 | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| root | ::1       | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
+------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)

mysql>

注意:

看某张表的内容:

bash
MariaDB [mysql]> select * from user;

image-20240329063235342

为什么会显示这样呢?

因为这个张表的列太多了,换行导致的。

只查看某2列内容:

bash
MariaDB [mysql]> select user,host from user;
+-------------+-------------+
| User        | Host        |
+-------------+-------------+
|             | localhost   |
| mariadb.sys | localhost   |
| mysql       | localhost   |
| root        | localhost   |
|             | vm-template |
+-------------+-------------+
5 rows in set (0.001 sec)

MariaDB [mysql]>

案例:查看用户名、密码

bash
mysql> select user,host,password from user;
+-----------+------+-------------------------------------------+
| Host      | User | Password                                  |
+-----------+------+-------------------------------------------+
| localhost | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| 127.0.0.1 | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
| ::1       | root | *ABE374A5F247C93961AD4726B39A5A84FA3BC3B1 |
+-----------+------+-------------------------------------------+
3 rows in set (0.00 sec)
  • 注意

查看用户密码:

bash
MariaDB [mysql]> select user,host,password,authentication_string from user;
+-------------+-------------+----------+-----------------------+
| User        | Host        | Password | authentication_string |
+-------------+-------------+----------+-----------------------+
| mariadb.sys | localhost   |          |                       |
| root        | localhost   | invalid  | invalid               |
| mysql       | localhost   | invalid  | invalid               |
|             | localhost   |          |                       |
|             | vm-template |          |                       |
+-------------+-------------+----------+-----------------------+
5 rows in set (0.001 sec)

MariaDB [mysql]> 

#password,authentication_string  密码可能存放在这2个字段,和数据版本有关;

限定只能在特定的主机上登录数据库:(加一个host)

基于安全因素考虑,设计了这个host的逻辑。

mysql用户,一部分叫用户名,一部分叫主机名。(主机名+用户名 合起来才叫一个完整的用户名)

image-20240329072117153

查看当前用户:

bash
status

image-20240329072746445

当前密码是空的:

bash
MariaDB [mysql]> select user,host,password from user;
+-------------+-------------+----------+
| User        | Host        | Password |
+-------------+-------------+----------+
| mariadb.sys | localhost   |          |
| root        | localhost   | invalid  |
| mysql       | localhost   | invalid  |
|             | localhost   |          |
|             | vm-template |          |
+-------------+-------------+----------+
5 rows in set (0.001 sec)

MariaDB [mysql]>

默认,使用mysql是直接能登陆数据库的:(密码是空的)

bash
mysql
==
mysql -uroot


[root@linux-test ~]#mysql ##默认省略了-uroot
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 11
Server version: 10.4.33-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

这里还存在空用户名:(表示匿名用户)

bash
MariaDB [mysql]> select user,host,password from user;
+-------------+-------------+----------+
| User        | Host        | Password |
+-------------+-------------+----------+
| mariadb.sys | localhost   |          |
| root        | localhost   | invalid  |
| mysql       | localhost   | invalid  |
|             | localhost   |          |
|             | vm-template |          |
+-------------+-------------+----------+
5 rows in set (0.001 sec)

MariaDB [mysql]>

image-20240329073607544

表示随便一个用户都可以登录:

bash
[root@linux-test ~]#mysql -uxyy
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 12
Server version: 10.4.33-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

image-20240329073519454

当前,这个匿名用户是一个普通用户,其权限很小的

bash
#只能看到2个数据库:
MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| test               |
+--------------------+
2 rows in set (0.001 sec)

MariaDB [(none)]> 

#当然也无法进入到mysql数据库:
MariaDB [(none)]> use mysql
ERROR 1044 (42000): Access denied for user ''@'localhost' to database 'mysql'
MariaDB [(none)]>

从很多方便来看,默认数据库安装好后,有很多不安全的地方:

注意:

这里有个情况,我切换到xyy用户,然后直接登录mysql,此时mysql里的用户会使哪个呢?

bash
[root@linux-test ~]#su - xyy
[xyy@linux-test ~]$mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 13
Server version: 10.4.33-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> status
--------------
mysql  Ver 15.1 Distrib 10.4.33-MariaDB, for Linux (x86_64) using readline 5.1

Connection id:          13
Current database:
Current user:           xyy@localhost
SSL:                    Not in use
Current pager:          stdout
Using outfile:          ''
Using delimiter:        ;
Server:                 MariaDB
Server version:         10.4.33-MariaDB MariaDB Server
Protocol version:       10
Connection:             Localhost via UNIX socket
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    utf8
Conn.  characterset:    utf8
UNIX socket:            /var/lib/mysql/mysql.sock
Uptime:                 1 hour 40 min 47 sec

Threads: 7  Questions: 150  Slow queries: 0  Opens: 37  Flush tables: 1  Open tables: 30  Queries per second avg: 0.024
--------------

MariaDB [(none)]> use mysql;
ERROR 1044 (42000): Access denied for user ''@'localhost' to database 'mysql'
MariaDB [(none)]>

可以看到是匿名用户登录。

如果我指定以root身份登录呢?

bash
[xyy@linux-test ~]$mysql -uroot
ERROR 1698 (28000): Access denied for user 'root'@'localhost'
[xyy@linux-test ~]$

会报错,无权限。

那么,这个是什么原因呢,是和版本有关。(我现在用的是10.4)

在10.3版本里:

可以看到,切换到普通用户登录mysql时,默认是以root身份登录上去的。

image-20240329074850329

image-20240329074905668

因此,在早期mysql版本里,基本没安全可言:

任何账户都可以以root账户登录数据库,以任何匿名账户都可以登录数据库。

因此:这里要做安全加固的。


范例:%代表从任何机器都可以访问mysql

bash
select user,host  from user;命令查看mysql用户名里时,host字段一个%代表什么意思?

在 MySQL 中,user 表位于 mysql 数据库中,用于存储数据库用户的信息。通过运行 SELECT user, host FROM mysql.user; 命令,你可以查看现有的数据库用户及其关联的主机信息。

在这个表中,host 字段表示用户可以从哪些主机连接到 MySQL 服务器。字段值中的 % 符号是一个通配符,表示任何主机。具体来说:

  • host 字段的值为 % 时,表示该用户可以从任意主机连接到 MySQL 服务器。

例如,如果你有以下记录:

user     | host
---------|-----
alice    | %
bob      | localhost
  • alice 用户可以从任何主机连接到 MySQL 服务器。
  • bob 用户只能从 localhost(本地主机)连接到 MySQL 服务器。

使用 % 作为通配符在某些情况下很有用,但需要注意的是,这样做可能会带来安全风险,因为它允许从任意主机进行连接。如果不需要这种全局访问权限,最好将 host 字段限制为特定的主机或IP地址以增强安全性。

查看当前用户

root:mysql里的超级用户。

我们现在登录的就是这个root账号:

查看当前登录用户:

方法1:

bash
mysql> select User();
+----------------+
| User()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

mysql>

方法2:status

bash
mysql> \s
--------------
mysql  Ver 14.14 Distrib 5.6.47, for linux-glibc2.12 (x86_64) using  EditLine wrapper

Connection id:          8
Current database:       mysql
Current user:           root@localhost
SSL:                    Not in use
Current pager:          stdout
Using outfile:          ''
Using delimiter:        ;
Server version:         5.6.47 MySQL Community Server (GPL)
Protocol version:       10
Connection:             Localhost via UNIX socket
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    utf8
Conn.  characterset:    utf8
UNIX socket:            /tmp/mysql.sock
Uptime:                 16 days 22 hours 45 min 27 sec

Threads: 1  Questions: 46  Slow queries: 0  Opens: 87  Flush tables: 1  Open tables: 80  Queries per second avg: 0.000
--------------

mysql>

查看某张表所有列的内容

bash
MariaDB [mysql]> desc user;
+------------------------+---------------------+------+-----+----------+-------+
| Field                  | Type                | Null | Key | Default  | Extra |
+------------------------+---------------------+------+-----+----------+-------+
| Host                   | char(60)            | NO   |     |          |       |
| User                   | char(80)            | NO   |     |          |       |
| Password               | longtext            | YES  |     | NULL     |       |
| Select_priv            | varchar(1)          | YES  |     | NULL     |       |
| Insert_priv            | varchar(1)          | YES  |     | NULL     |       |
| Update_priv            | varchar(1)          | YES  |     | NULL     |       |
| Delete_priv            | varchar(1)          | YES  |     | NULL     |       |
| Create_priv            | varchar(1)          | YES  |     | NULL     |       |
| Drop_priv              | varchar(1)          | YES  |     | NULL     |       |
| Reload_priv            | varchar(1)          | YES  |     | NULL     |       |
| Shutdown_priv          | varchar(1)          | YES  |     | NULL     |       |
| Process_priv           | varchar(1)          | YES  |     | NULL     |       |
| File_priv              | varchar(1)          | YES  |     | NULL     |       |

查看支持所有的字符集

bash
mysql> SHOW CHARACTER SET;
+----------+-----------------------------+---------------------+--------+
| 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 |
| euckr    | EUC-KR Korean               | euckr_korean_ci     |      2 |
| koi8u    | KOI8-U Ukrainian            | koi8u_general_ci    |      1 |
| gb2312   | GB2312 Simplified Chinese   | gb2312_chinese_ci   |      2 |
| greek    | ISO 8859-7 Greek            | greek_general_ci    |      1 |
| cp1250   | Windows Central European    | cp1250_general_ci   |      1 |
| gbk      | GBK Simplified Chinese      | gbk_chinese_ci      |      2 |
| latin5   | ISO 8859-9 Turkish          | latin5_turkish_ci   |      1 |
| armscii8 | ARMSCII-8 Armenian          | armscii8_general_ci |      1 |
| utf8     | UTF-8 Unicode               | utf8_general_ci     |      3 |
| ucs2     | UCS-2 Unicode               | ucs2_general_ci     |      2 |
| cp866    | DOS Russian                 | cp866_general_ci    |      1 |
| keybcs2  | DOS Kamenicky Czech-Slovak  | keybcs2_general_ci  |      1 |
| macce    | Mac Central European        | macce_general_ci    |      1 |
| macroman | Mac West European           | macroman_general_ci |      1 |
| cp852    | DOS Central European        | cp852_general_ci    |      1 |
| latin7   | ISO 8859-13 Baltic          | latin7_general_ci   |      1 |
| utf8mb4  | UTF-8 Unicode               | utf8mb4_general_ci  |      4 |
| cp1251   | Windows Cyrillic            | cp1251_general_ci   |      1 |
| utf16    | UTF-16 Unicode              | utf16_general_ci    |      4 |
| utf16le  | UTF-16LE Unicode            | utf16le_general_ci  |      4 |
| cp1256   | Windows Arabic              | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic              | cp1257_general_ci   |      1 |
| utf32    | UTF-32 Unicode              | utf32_general_ci    |      4 |
| binary   | Binary pseudo charset       | binary              |      1 |
| geostd8  | GEOSTD8 Georgian            | geostd8_general_ci  |      1 |
| cp932    | SJIS for Windows Japanese   | cp932_japanese_ci   |      2 |
| eucjpms  | UJIS for Windows Japanese   | eucjpms_japanese_ci |      3 |
+----------+-----------------------------+---------------------+--------+
40 rows in set (0.01 sec)

mysql>

范例:字符集相关文件

bash
[root@linux-test ~]#ll /usr/share/mysql/charsets/
total 232
-rw-r--r--. 1 root root  5526 Apr 20  2018 armscii8.xml
-rw-r--r--. 1 root root  5512 Apr 20  2018 ascii.xml
-rw-r--r--. 1 root root  8241 Apr 20  2018 cp1250.xml
-rw-r--r--. 1 root root  8365 Apr 20  2018 cp1251.xml
-rw-r--r--. 1 root root  5569 Apr 20  2018 cp1256.xml
-rw-r--r--. 1 root root  8902 Apr 20  2018 cp1257.xml
-rw-r--r--. 1 root root  5506 Apr 20  2018 cp850.xml
-rw-r--r--. 1 root root  5528 Apr 20  2018 cp852.xml
-rw-r--r--. 1 root root  5613 Apr 20  2018 cp866.xml
-rw-r--r--. 1 root root  6529 Apr 20  2018 dec8.xml
-rw-r--r--. 1 root root  5516 Apr 20  2018 geostd8.xml
-rw-r--r--. 1 root root  5728 Apr 20  2018 greek.xml
-rw-r--r--. 1 root root  5517 Apr 20  2018 hebrew.xml
-rw-r--r--. 1 root root  5502 Apr 20  2018 hp8.xml
-rw-r--r--. 1 root root 18307 Apr 20  2018 Index.xml
-rw-r--r--. 1 root root  5529 Apr 20  2018 keybcs2.xml
-rw-r--r--. 1 root root  5510 Apr 20  2018 koi8r.xml
-rw-r--r--. 1 root root  6532 Apr 20  2018 koi8u.xml
-rw-r--r--. 1 root root  9816 Apr 20  2018 latin1.xml
-rw-r--r--. 1 root root  7238 Apr 20  2018 latin2.xml
-rw-r--r--. 1 root root  5515 Apr 20  2018 latin5.xml
-rw-r--r--. 1 root root  7438 Apr 20  2018 latin7.xml
-rw-r--r--. 1 root root  8047 Apr 20  2018 macce.xml
-rw-r--r--. 1 root root  8058 Apr 20  2018 macroman.xml
-rw-r--r--. 1 root root  1749 Apr 20  2018 README
-rw-r--r--. 1 root root  6530 Apr 20  2018 swe7.xml
[root@linux-test ~]#

查看当前字符集的使用情况

bash
mysql> show variables like 'character%';
+--------------------------+----------------------------------------------------------------+
| Variable_name            | Value                                                          |
+--------------------------+----------------------------------------------------------------+
| character_set_client     | utf8                                                           |
| character_set_connection | utf8                                                           |
| character_set_database   | latin1                                                         |
| character_set_filesystem | binary                                                         |
| character_set_results    | utf8                                                           |
| character_set_server     | latin1                                                         |
| character_set_system     | utf8                                                           |
| character_sets_dir       | /usr/local/mysql-5.6.47-linux-glibc2.12-x86_64/share/charsets/ |
+--------------------------+----------------------------------------------------------------+
8 rows in set (0.00 sec)

mysql>

查看支持所有排序规则

bash
mysql> show COLLATION;

查看当前使用的排序规则

bash
mysql> SHOW VARIABLES LIKE 'collation%';
+----------------------+-------------------+
| Variable_name        | Value             |
+----------------------+-------------------+
| collation_connection | utf8_general_ci   |
| collation_database   | latin1_swedish_ci |
| collation_server     | latin1_swedish_ci |
+----------------------+-------------------+
3 rows in set (0.00 sec)

mysql>

查看当前连接数据库的端口

bash
mysql> show variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.00 sec)


mysql> show variables like 'PORT';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.01 sec)

mysql>

创建数据库

sql
CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME'
CHARACTER SET 'character set name'
COLLATE 'collate name';


CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME';


CREATE DATABASE|SCHEMA 'DB_NAME';

🍊 范例:创建数据库

sql
mysql> create database db1;
Query OK, 1 row affected (0.00 sec)

mysql> show create database db1;
+----------+-----------------------------------------------------------------+
| Database | Create Database                                                 |
+----------+-----------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8mb4 */ |
+----------+-----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> 
[root@linux-test ~]#cat /data/mysql/db1/db.opt 
default-character-set=utf8mb4
default-collation=utf8mb4_general_ci
[root@linux-test ~]#



mysql> create database db1;
ERROR 1007 (HY000): Can't create database 'db1'; database exists
mysql> create database IF NOT EXISTS db1;
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> show warnings;
+-------+------+----------------------------------------------+
| Level | Code | Message                                      |
+-------+------+----------------------------------------------+
| Note  | 1007 | Can't create database 'db1'; database exists |
+-------+------+----------------------------------------------+
1 row in set (0.00 sec)

mysql>

🍊 范例:指定字符集创建新数据库

sql
mysql> create database IF NOT EXISTS db2 CHARACTER SET 'utf8';
Query OK, 1 row affected (0.01 sec)

mysql> show create database db2;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| db2      | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> 


default-character-set=utf8
default-collation=utf8_general_ci
[root@linux-test ~]#

修改数据库的字符集

sql
mysql> show create database db1;
+----------+-----------------------------------------------------------------+
| Database | Create Database                                                 |
+----------+-----------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8mb4 */ |
+----------+-----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> alter database db1 character set utf8;
Query OK, 1 row affected (0.00 sec)

mysql> show create database db1;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> 

[root@linux-test ~]#cat /data/mysql/db1/db.opt 
default-character-set=utf8
default-collation=utf8_general_ci
[root@linux-test ~]#

删除数据库

sql
DROP DATABASE|SCHEMA [IF EXISTS] 'DB_NAME';

🍊 范例:删除数据库

sql
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db1                |
| db2                |
| mysql              |
| performance_schema |
+--------------------+
5 rows in set (0.00 sec)

mysql> drop database db1;
Query OK, 0 rows affected (0.02 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db2                |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

mysql> 

[root@linux-test ~]#ls /data/mysql/db1
ls: cannot access /data/mysql/db1: No such file or directory
[root@linux-test ~]#

🍊 范例:如果在数据库目录里创建一个文件,删除数据库后,还能删除这个数据库目录吗

sql
[root@linux-test ~]#ll /data/mysql/db2
total 4
-rw-rw---- 1 mysql mysql 61 Apr 23 07:04 db.opt
[root@linux-test ~]#touch /data/mysql/db2/xxx.txt
[root@linux-test ~]#ll /data/mysql/db2
total 4
-rw-rw---- 1 mysql mysql 61 Apr 23 07:04 db.opt
-rw-r--r-- 1 root  root   0 Apr 23 07:25 xxx.txt
[root@linux-test ~]#


mysql> drop database db2;
ERROR 1010 (HY000): Error dropping database (can't rmdir './db2/', errno: 17)
mysql> 
                                             
#修改权限                                             
[root@linux-test ~]#ll /data/mysql/db2
total 0
-rw-r--r-- 1 root root 0 Apr 23 07:25 xxx.txt
[root@linux-test ~]#chown -R mysql.mysql  /data/mysql/
[root@linux-test ~]#ll /data/mysql/db2
total 0
-rw-r--r-- 1 mysql mysql 0 Apr 23 07:25 xxx.txt
[root@linux-test ~]# 
 
                                             
#再次删除还是报错……                                            
mysql> drop database db2;
ERROR 1010 (HY000): Error dropping database (can't rmdir './db2/', errno: 17)
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db2                |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

mysql>

🍊 范例:删除mysql数据库(自杀)

sql
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db2                |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

mysql> drop database mysql;
Query OK, 28 rows affected, 2 warnings (0.03 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db2                |
| performance_schema |
+--------------------+
3 rows in set (0.00 sec)

mysql> 


##删除mysql数据库后,停止mysql服务再次启动后,会报错的,完了,mysql废了哈哈😂
[root@linux-test ~]#systemctl status mysql
mysqld.service - LSB: start and stop MySQL
   Loaded: loaded (/etc/rc.d/init.d/mysqld; bad; vendor preset: disabled)
   Active: active (running) since Tue 2024-04-23 06:40:40 CST; 47min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 6518 ExecStart=/etc/rc.d/init.d/mysqld start (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/mysqld.service
           ├─6536 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/linux...
           └─6788 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/...

Apr 23 06:40:40 linux-test systemd[1]: Starting LSB: start and stop MySQL...
Apr 23 06:40:40 linux-test mysqld[6518]: Starting MySQL SUCCESS!
Apr 23 06:40:40 linux-test systemd[1]: Started LSB: start and stop MySQL.
[root@linux-test ~]#systemctl stop  mysql
[root@linux-test ~]#systemctl start   mysql
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
[root@linux-test ~]#
[root@linux-test ~]#netstat -ntlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      6514/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      6877/master         
tcp6       0      0 :::22                   :::*                    LISTEN      6514/sshd           
tcp6       0      0 ::1:25                  :::*                    LISTEN      6877/master         
[root@linux-test ~]#

直接指定对应数据库

就不需要再次使用use来特地登录数据库了:

sql
[root@linux-test ~]#mysql -uroot -pxyy520 test
Warning: Using a password on the command line interface can be insecure.
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.6.47 MySQL Community Server (GPL)

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

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 tables;
+----------------+
| Tables_in_test |
+----------------+
| autiinc1       |
| student        |
| student2       |
| t1             |
| t2             |
| testdate       |
| testdate2      |
| testdate3      |
+----------------+
8 rows in set (0.00 sec)

mysql>

2种写法都可以的

sql
mysql> select * from t1;
+----+
| id |
+----+
|  1 |
|  2 |
+----+
2 rows in set (0.00 sec)

mysql> select *from t1;
+----+
| id |
+----+
|  1 |
|  2 |
+----+
2 rows in set (0.00 sec)

创建复合主键的方式

sql
CREATE TABLE student_info (
 stu_id INT(11) NOT NULL AUTO_INCREMENT ,
 stu_name VARCHAR(255) DEFAULT NULL,
  PRIMARY KEY (stu_id,stu_name)
);

查看mysql线程

sql
06:37:52(root@localhost) [hellodb]> show processlist; 
+----+-------------+-------------------+---------+---------+------+--------------------------+------------------+----------+
| Id | User        | Host              | db      | Command | Time | State                    | Info             | Progress |
+----+-------------+-------------------+---------+---------+------+--------------------------+------------------+----------+
|  2 | system user |                   | NULL    | Daemon  | NULL | InnoDB purge coordinator | NULL             |    0.000 |
|  1 | system user |                   | NULL    | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  3 | system user |                   | NULL    | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  4 | system user |                   | NULL    | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  5 | system user |                   | NULL    | Daemon  | NULL | InnoDB shutdown handler  | NULL             |    0.000 |
| 13 | admin       | 172.29.9.31:38934 | NULL    | Sleep   | 3199 |                          | NULL             |    0.000 |
| 29 | root        | localhost         | hellodb | Query   |    0 | Init                     | show processlist |    0.000 |
+----+-------------+-------------------+---------+---------+------+--------------------------+------------------+----------+
7 rows in set (0.000 sec)

mysql客户端命令

  • 客户端命令:本地执行,每个命令都完整形式和简写格式
bash
mysql> \h, help
mysql> \u,use
mysql> \s,status
mysql> \!,system  #(和awk里的system()功能类似) Execute a system shell command.
bash
MariaDB [mysql]> help

General information about MariaDB can be found at
http://mariadb.org

List of all client commands:
Note that all text commands must be first on line and end with ';'
?         (\?) Synonym for `help'.
clear     (\c) Clear the current input statement.
connect   (\r) Reconnect to the server. Optional arguments are db and host.
delimiter (\d) Set statement delimiter.
edit      (\e) Edit command with $EDITOR.
ego       (\G) Send command to MariaDB server, display result vertically.
exit      (\q) Exit mysql. Same as quit.  ##常用
go        (\g) Send command to MariaDB server.
help      (\h) Display this help.   ##常用
nopager   (\n) Disable pager, print to stdout.
notee     (\t) Don't write into outfile.
pager     (\P) Set PAGER [to_pager]. Print the query results via PAGER.
print     (\p) Print current command.
prompt    (\R) Change your mysql prompt.
quit      (\q) Quit mysql.
rehash    (\#) Rebuild completion hash.
source    (\.) Execute an SQL script file. Takes a file name as an argument.
status    (\s) Get status information from the server.   ##常用
system    (\!) Execute a system shell command. ##常用
tee       (\T) Set outfile [to_outfile]. Append everything into given outfile.
use       (\u) Use another database. Takes database name as argument.
charset   (\C) Switch to another charset. Might be needed for processing binlog with multi-byte charsets.
warnings  (\W) Show warnings after every statement.
nowarning (\w) Don't show warnings after every statement.

For server side help, type 'help contents'

MariaDB [mysql]>

举例:(和awk里的system()功能类似) \!

bash
system    (\!) Execute a system shell command.

MariaDB [(none)]> system ls
MariaDB [(none)]> system date
Sat Mar 30 12:17:32 CST 2024
MariaDB [(none)]> system pwd
/root
MariaDB [(none)]>

举例:souce 用sql语言写的sql脚本

bash
cat > test.sql <<EOF
use mysql
select user,host from user;
EOF

[root@linux-test ~]#cat test.sql 
use mysql
select user,host from user;
[root@linux-test ~]#


[root@linux-test ~]#mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 12
Server version: 10.4.33-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> source test.sql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
+-------------+-----------+
| User        | Host      |
+-------------+-----------+
| mariadb.sys | localhost |
| mysql       | localhost |
| root        | localhost |
+-------------+-----------+
3 rows in set (0.001 sec)

MariaDB [mysql]> 


MariaDB [mysql]> \. test.sql
Database changed
+-------------+-----------+
| User        | Host      |
+-------------+-----------+
| mariadb.sys | localhost |
| mysql       | localhost |
| root        | localhost |
+-------------+-----------+
3 rows in set (0.000 sec)

MariaDB [mysql]> 


#指定路径
MariaDB [mysql]> system ls -l /tmp/test.sql
-rw-r--r-- 1 root root 38 Mar 30 12:27 /tmp/test.sql
MariaDB [mysql]> \. /tmp/test.sql
Database changed
+-------------+-----------+
| User        | Host      |
+-------------+-----------+
| mariadb.sys | localhost |
| mysql       | localhost |
| root        | localhost |
+-------------+-----------+
3 rows in set (0.001 sec)

MariaDB [mysql]>

举例:mysql-e选项 非交互式方式

bash
[root@linux-test ~]#mysql --help
……
  -e, --execute=name  Execute command and quit. (Disables --force and history
                      file.)
                      
[root@linux-test ~]#mysql -uroot -pxyy520 -e '\s'
--------------
mysql  Ver 15.1 Distrib 10.4.33-MariaDB, for Linux (x86_64) using readline 5.1

Connection id:          14
Current database:
Current user:           root@localhost
SSL:                    Not in use
Current pager:          stdout
Using outfile:          ''
Using delimiter:        ;
Server:                 MariaDB
Server version:         10.4.33-MariaDB MariaDB Server
Protocol version:       10
Connection:             Localhost via UNIX socket
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    utf8
Conn.  characterset:    utf8
UNIX socket:            /var/lib/mysql/mysql.sock
Uptime:                 2 hours 15 min 18 sec

Threads: 6  Questions: 98  Slow queries: 0  Opens: 37  Flush tables: 1  Open tables: 30  Queries per second avg: 0.012
--------------

[root@linux-test ~]#

mysqladmin命令

mysqladmin 命令格式

bash
mysqladmin [OPTIONS] command command....

范例:

bash
#查看mysql服务是否正常,如果正常提示mysqld is alive
[root@linux-test ~]#mysqladmin -uroot -pxyy520 ping
mysqld is alive


#关闭mysql服务,但mysqladmin命令无法开启
mysqladmin –uroot –pcentos shutdown ##这个方式是比较安全的,也是比较推荐的,它可以正常关闭数据库。  systemctl stop mariadb



#创建数据库testdb
mysqladmin -uroot –pcentos   create testdb 
#删除数据库testdb
mysqladmin -uroot -pcentos   drop testdb


#修改root密码
mysqladmin –uroot –pcentos password 'magedu'

#日志滚动,生成新文件/var/lib/mysql/mariadb-bin.00000N
mysqladmin -uroot -pcentos flush-logs

#查看变量
mysqladmin variables |grep port

SQL语言帮助文档

获取SQL 命令使用帮助:

bash
mysql> HELP KEYWORD

官方帮助:https://dev.mysql.com/doc/refman/8.0/en/sql-statements.html

image-20240422064900943

范例:删除mysql空用户

工作里遇到的。

bash
mysql -uroot -p123456

use mysql;
select user,host from user;

delete from mysql.user where Host="localhost" and User="";

image-20240516174215313

范例:修改mysql用户密码

关于我

我的博客主旨:

  • 排版美观,语言精炼;
  • 文档即手册,步骤明细,拒绝埋坑,提供源码;
  • 本人实战文档都是亲测成功的,各位小伙伴在实际操作过程中如有什么疑问,可随时联系本人帮您解决问题,让我们一起进步!

🍀 微信二维码

x2675263825 (舍得), qq:2675263825。

image-20230107215114763

🍀 微信公众号

《云原生架构师实战》

image-20230107215126971

🍀 个人博客站点

https://onedayxyy.cn/

🍀 语雀

https://www.yuque.com/xyy-onlyone

🍀 csdn

https://blog.csdn.net/weixin_39246554?spm=1010.2135.3001.5421

image-20230107215149885

🍀 知乎

https://www.zhihu.com/people/foryouone

image-20230107215203185

最后

好了,关于本次就到这里了,感谢大家阅读,最后祝大家生活快乐,每天都过的有意义哦,我们下期见!

声明

作者:One

版权:此文章版权归 One 所有,如有转载,请注明出处!

链接:可点击右上角分享此页面复制文章链接

上次更新时间:

最近更新