一、mysql环境的配置
1.环境准备
（1）主数据库
#关闭防火墙
[root@master ~]# systemctl stop firewalld
#关闭selinux
[root@master ~]# setenforce 0
#下载lrzsz工具
[root@master ~]# yum -y install lrzsz
#安装rsync
[root@master ~]# yum -y install rsync
#查看是否安装了libaio
[root@master ~]# rpm -qa|grep libaio
libaio-0.3.109-13.el7.x86_64
#查看是否安装了rsync
[root@master ~]# rpm -qa|grep rsync
rsync-3.1.2-12.el7_9.x86_64（2）从数据库
#关闭防火墙
[root@slave ~]# systemctl stop firewalld
#关闭selinux
[root@slave ~]# setenforce 0
#安装lrzsz
[root@slave ~]# yum -y install lrzsz
#安装rsync
[root@slave ~]# yum -y install rsync2.解压
（1）主数据库
# 将mysqlmysql-8.0.33-linux-glibc2.12-x86_64.tar包拖到xshell中
[root@master ~]# rz -E
rz waiting to receive.
[root@master ~]# ls
anaconda-ks.cfg mysql-8.0.33-linux-glibc2.12-x86_64.tar
# 解压
[root@master ~]# tar -xf mysql-8.0.33-linux-glibc2.12-x86_64.tar
[root@master ~]# tar -xf mysql-8.0.33-linux-glibc2.12-x86_64.tar.xz
# 查看是否解压成功
[root@master ~]# ls
anaconda-ks.cfg
mysql-8.0.33-linux-glibc2.12-x86_64
mysql-8.0.33-linux-glibc2.12-x86_64.tar
mysql-8.0.33-linux-glibc2.12-x86_64.tar.xz
mysql-router-8.0.33-linux-glibc2.12-x86_64.tar.xz
mysql-test-8.0.33-linux-glibc2.12-x86_64.tar.xz（2）从数据库
[root@slave ~]# ls
anaconda-ks.cfg mysql-8.0.33-linux-glibc2.12-x86_64.tar
[root@slave ~]# tar -xf mysql-8.0.33-linux-glibc2.12-x86_64.tar
[root@slave ~]# tar -xf mysql-8.0.33-linux-glibc2.12-x86_64.tar.xz
[root@slave ~]# ls
anaconda-ks.cfg
mysql-8.0.33-linux-glibc2.12-x86_64
mysql-8.0.33-linux-glibc2.12-x86_64.tar
mysql-8.0.33-linux-glibc2.12-x86_64.tar.xz
mysql-router-8.0.33-linux-glibc2.12-x86_64.tar.xz
mysql-test-8.0.33-linux-glibc2.12-x86_64.tar.xz3.备份文件
（1）主数据库
[root@master ~]# cp -r mysql-8.0.33-linux-glibc2.12-x86_64 /usr/local/mysql（2）从数据库
[root@slave ~]# cp -r mysql-8.0.33-linux-glibc2.12-x86_64 /usr/local/mysql4.创建目录和用户
（1）主数据库
[root@master ~]# cd /usr/local/mysql/
[root@master mysql]# ls
bin docs include lib LICENSE man README share support-files
[root@master mysql]# mkdir mysql-files
[root@master mysql]# ll
总用量 292
drwxr-xr-x. 2 root root 4096 8月 7 09:21 bin
drwxr-xr-x. 2 root root 38 8月 7 09:21 docs
drwxr-xr-x. 3 root root 282 8月 7 09:21 include
drwxr-xr-x. 6 root root 201 8月 7 09:21 lib
-rw-r--r--. 1 root root 284945 8月 7 09:21 LICENSE
drwxr-xr-x. 4 root root 30 8月 7 09:21 man
drwxr-xr-x. 2 root root 6 8月 7 09:22 mysql-files
-rw-r--r--. 1 root root 666 8月 7 09:21 README
drwxr-xr-x. 28 root root 4096 8月 7 09:21 share
drwxr-xr-x. 2 root root 77 8月 7 09:21 support-files
[root@master mysql]# id mysql
id: mysql: no such user
[root@master mysql]# useradd -r -s /sbin/nologin mysql
[root@master mysql]# id mysql
uid=997(mysql) gid=995(mysql) 组=995(mysql)
[root@master mysql]# echo $?
0（2）从数据库
[root@slave ~]# mkdir /usr/local/mysql/mysql-files
[root@slave ~]# useradd -r -s /sbin/nologin mysql
[root@slave ~]# id mysql
uid=997(mysql) gid=995(mysql) 组=995(mysql)
5.修改权限
（1）主数据库
[root@master mysql]# chown mysql:mysql ./mysql-files/
[root@master mysql]# ll
总用量 292
drwxr-xr-x. 2 root root 4096 8月 7 09:21 bin
drwxr-xr-x. 2 root root 38 8月 7 09:21 docs
drwxr-xr-x. 3 root root 282 8月 7 09:21 include
drwxr-xr-x. 6 root root 201 8月 7 09:21 lib
-rw-r--r--. 1 root root 284945 8月 7 09:21 LICENSE
drwxr-xr-x. 4 root root 30 8月 7 09:21 man
drwxr-xr-x. 2 mysql mysql 6 8月 7 09:22 mysql-files
-rw-r--r--. 1 root root 666 8月 7 09:21 README
drwxr-xr-x. 28 root root 4096 8月 7 09:21 share
drwxr-xr-x. 2 root root 77 8月 7 09:21 support-files（2）从数据库
[root@slave ~]# chown mysql:mysql /usr/local/mysql/mysql-files
[root@slave ~]# ll /usr/local/mysql/
总用量 292
drwxr-xr-x. 2 root root 4096 8月 7 10:07 bin
drwxr-xr-x. 2 root root 38 8月 7 10:07 docs
drwxr-xr-x. 3 root root 282 8月 7 10:07 include
drwxr-xr-x. 6 root root 201 8月 7 10:07 lib
-rw-r--r--. 1 root root 284945 8月 7 10:07 LICENSE
drwxr-xr-x. 4 root root 30 8月 7 10:07 man
drwxr-xr-x. 2 mysql mysql 6 8月 7 10:11 mysql-files
-rw-r--r--. 1 root root 666 8月 7 10:07 README
drwxr-xr-x. 28 root root 4096 8月 7 10:07 share
drwxr-xr-x. 2 root root 77 8月 7 10:07 support-files6.删除配置文件
（1）主数据库
[root@master mysql]# rm -rf /etc/my.cnf（2）从数据库
[root@slave ~]# rm -rf /etc/my.cnf7.初始化
（1）主数据库
# 初始化 从数据库不能初始化
[root@master mysql]# ./bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql
2024-08-07T01:28:33.413323Z 0 [System][MY-013169] [Server] /usr/local/mysql/bin/mysqld (mysqld 8.0.33) initializing of server in progress as process 1701
2024-08-07T01:28:33.420601Z 1 [System][MY-013576] [InnoDB] InnoDB initialization has started.
2024-08-07T01:28:34.159124Z 1 [System][MY-013577] [InnoDB] InnoDB initialization has ended.
2024-08-07T01:28:35.485851Z 6 [Note][MY-010454] [Server] A temporary password is generated for root@localhost: CpjsNb1yO-fd
[root@master mysql]# ls /usr/local/mysql
bin docs lib man README support-files
data include LICENSE mysql-files share
[root@master mysql]# ll
总用量 296
drwxr-xr-x. 2 root root 4096 8月 7 09:21 bin
drwxr-x---. 7 mysql mysql 4096 8月 7 09:28 data
drwxr-xr-x. 2 root root 38 8月 7 09:21 docs
drwxr-xr-x. 3 root root 282 8月 7 09:21 include
drwxr-xr-x. 6 root root 201 8月 7 09:21 lib
-rw-r--r--. 1 root root 284945 8月 7 09:21 LICENSE
drwxr-xr-x. 4 root root 30 8月 7 09:21 man
drwxr-xr-x. 2 mysql mysql 6 8月 7 09:22 mysql-files
-rw-r--r--. 1 root root 666 8月 7 09:21 README
drwxr-xr-x. 28 root root 4096 8月 7 09:21 share
drwxr-xr-x. 2 root root 77 8月 7 09:21 support-files
[root@master mysql]# ./bin/mysql_ssl_rsa_setup --datadir=/usr/local/mysql/data（2）从数据库
从数据库不能初始化
8.其他配置
（1）主数据库
[root@master mysql]# cp support-files/mysql.server /etc/init.d/mysql8（2）从数据库
[root@slave ~]# cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql89.修改主数据库的my.cnf配置文件
#修改配置文件
[root@master mysql]# vim my.cnf
[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
port=3306
#启动mysql服务
[root@master mysql]# service mysql8 start
Starting MySQL.Logging to '/usr/local/mysql/data/master.err'.
. SUCCESS!
#登录mysql
[root@master mysql]# ./bin/mysql -P3306 -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.33
Copyright (c) 2000, 2023, 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> alter user 'root'@'localhost' identified by 'Hui@2003';
Query OK, 0 rows affected (0.00 sec)
#退出
mysql> quit
Bye
#在my.cnf中继续添加内容
[root@master mysql]# vim my.cnf
[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
port=3306
log-error=/usr/local/mysql/data/db01-master.err
log-bin=/usr/local/mysql/data/binlog
server-id=10
character_set_server=utf8mb4
#启动服务
[root@master mysql]# service mysql8 start
Starting MySQL SUCCESS!
#登录mysql
[root@master mysql]# ./bin/mysql -P3306 -pHui@2003
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 9
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, 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.
#退出
mysql> quit
Bye10.查看主数据库中目录的信息
#查看data目录
[root@master mysql]# ls -l data/
总用量 90572
-rw-r-----. 1 mysql mysql 56 8月 7 09:28 auto.cnf
-rw-r-----. 1 mysql mysql 477 8月 7 09:40 binlog.000001
-rw-r-----. 1 mysql mysql 16 8月 7 09:37 binlog.index
-rw-------. 1 mysql mysql 1680 8月 7 09:28 ca-key.pem
-rw-r--r--. 1 mysql mysql 1112 8月 7 09:28 ca.pem
-rw-r--r--. 1 mysql mysql 1112 8月 7 09:28 client-cert.pem
-rw-------. 1 mysql mysql 1680 8月 7 09:28 client-key.pem
-rw-r-----. 1 mysql mysql 196608 8月 7 09:40 #ib_16384_0.dblwr
-rw-r-----. 1 mysql mysql 8585216 8月 7 09:28 #ib_16384_1.dblwr
-rw-r-----. 1 mysql mysql 5985 8月 7 09:28 ib_buffer_pool
-rw-r-----. 1 mysql mysql 12582912 8月 7 09:40 ibdata1
-rw-r-----. 1 mysql mysql 12582912 8月 7 09:37 ibtmp1
drwxr-x---. 2 mysql mysql 4096 8月 7 09:37 #innodb_redo
drwxr-x---. 2 mysql mysql 187 8月 7 09:37 #innodb_temp
-rw-r-----. 1 mysql mysql 929 8月 7 09:37 master.err
-rw-r-----. 1 mysql mysql 5 8月 7 09:37 master.pid
drwxr-x---. 2 mysql mysql 143 8月 7 09:28 mysql
-rw-r-----. 1 mysql mysql 25165824 8月 7 09:40 mysql.ibd
drwxr-x---. 2 mysql mysql 8192 8月 7 09:28 performance_schema
-rw-------. 1 mysql mysql 1676 8月 7 09:28 private_key.pem
-rw-r--r--. 1 mysql mysql 452 8月 7 09:28 public_key.pem
-rw-r--r--. 1 mysql mysql 1112 8月 7 09:28 server-cert.pem
-rw-------. 1 mysql mysql 1680 8月 7 09:28 server-key.pem
drwxr-x---. 2 mysql mysql 28 8月 7 09:28 sys
-rw-r-----. 1 mysql mysql 16777216 8月 7 09:39 undo_001
-rw-r-----. 1 mysql mysql 16777216 8月 7 09:40 undo_002
#查看错误日志
[root@master mysql]# cat data/master.err
2024-08-07T01:37:35.068359Z 0 [System][MY-010116] [Server] /usr/local/mysql/bin/mysqld (mysqld 8.0.33) starting as process 1925
2024-08-07T01:37:35.081787Z 1 [System][MY-013576] [InnoDB] InnoDB initialization has started.
2024-08-07T01:37:35.735592Z 1 [System][MY-013577] [InnoDB] InnoDB initialization has ended.
2024-08-07T01:37:36.273703Z 0 [Warning][MY-010068] [Server] CA certificate ca.pem is self signed.
2024-08-07T01:37:36.273749Z 0 [System][MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
2024-08-07T01:37:36.306295Z 0 [System][MY-010931] [Server] /usr/local/mysql/bin/mysqld: ready for connections. Version: '8.0.33' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server - GPL.
2024-08-07T01:37:36.306366Z 0 [System][MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /tmp/mysqlx.sock
#查看/tmp中的套接字的信息
[root@master mysql]# ll /tmp
总用量 12
-rwx------. 1 root root 836 8月 7 00:25 ks-script-pjA4To
srwxrwxrwx. 1 mysql mysql 0 8月 7 09:37 mysql.sock
-rw-------. 1 mysql mysql 5 8月 7 09:37 mysql.sock.lock
srwxrwxrwx. 1 mysql mysql 0 8月 7 09:37 mysqlx.sock
-rw-------. 1 mysql mysql 5 8月 7 09:37 mysqlx.sock.lock
drwx------. 3 root root 17 8月 7 09:06 systemd-private-4192ed53ab514a048ba1c51132c3e28f-chronyd.service-skAuWy
drwx------. 3 root root 17 8月 6 17:35 systemd-private-f93e9a7cc83a4e6ba1ea5a4ff1abcdc2-chronyd.service-2U7zsa
drwx------. 2 root root 6 8月 7 00:25 vmware-root
-rw-------. 1 root root 0 8月 7 00:21 yum.log11.进行数据同步
（1）主数据库
#停止mysql服务
[root@master ~]# service mysql8 stop
Shutting down MySQL. SUCCESS!
#删除/data中的auto.cnf
[root@master ~]# rm -rf /usr/local/mysql/data/auto.cnf
#查看是否删除
[root@master ~]# ls /usr/local/mysql/data/
binlog.000001 client-key.pem #innodb_redo performance_schema sys
binlog.index #ib_16384_0.dblwr #innodb_temp private_key.pem undo_001
ca-key.pem #ib_16384_1.dblwr master.err public_key.pem undo_002
ca.pem ib_buffer_pool mysql server-cert.pem
client-cert.pem ibdata1 mysql.ibd server-key.pem
#将主数据库中的data同步到从数据库中
[root@master ~]# rsync -av /usr/local/mysql/data root@192.168.2.39:/usr/local/mysql（2）从数据库
#在从库中查看有没有将data同步过来
[root@slave ~]# ls /usr/local/mysql
bin docs lib man README support-files
data include LICENSE mysql-files share
#查看是否将主库data中的auto.cnf同步过来
[root@slave ~]# ls /usr/local/mysql/data
binlog.000001 client-key.pem #innodb_redo performance_schema sys
binlog.index #ib_16384_0.dblwr #innodb_temp private_key.pem undo_001
ca-key.pem #ib_16384_1.dblwr master.err public_key.pem undo_002
ca.pem ib_buffer_pool mysql server-cert.pem
client-cert.pem ibdata1 mysql.ibd server-key.pem12.修改从数据库的my.cnf文件
[root@slave ~]# vim /usr/local/mysql/my.cnf
[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
log-error=/usr/local/mysql/data/err.log
relay-log=/usr/local/mysql/data/relaylog
character_set_server=utf8mb4
server-id=1113.启动服务
（1）主数据库
[root@master ~]# service mysql8 start
Starting MySQL.Logging to '/usr/local/mysql/data/db01-master.err'.
. SUCCESS! （2）从数据库
[root@slave ~]# service mysql8 start
Starting MySQL.Logging to '/usr/local/mysql/data/err.log'.
. SUCCESS! 14.将mysql添加到bin
（1）主数据库
#修改配置文件
[root@master ~]# vim /etc/profile
#在最后一行添加内容
export PATH=/usr/local/mysql/bin:$PATH
[root@master ~]# source /etc/profile
#尝试用mysql命令是否能进入
[root@master ~]# mysql -pHui@2003
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 8
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, 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>（2）从数据库
#修改配置文件
[root@slave ~]# vim /etc/profile
#在最后一行添加内容
export PATH=/usr/local/mysql/bin:$PATH
[root@slave ~]# source /etc/profile
#尝试用mysql命令是否能进入
[root@slave ~]# mysql -h192.168.2.38 -uslave --get-server-public-key -p
Enter password: slave_123;
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, 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
Bye15.在主数据库中创建账号
#创建slave账户
mysql> create user 'slave'@'192.168.2.%' identified by 'slave_123;'；
Query OK, 0 rows affected (0.02 sec)
#给slave账户所有权限
mysql> grant replication slave on *.* to 'slave'@'192.168.2.%';
Query OK, 0 rows affected (0.02 sec)
#刷新权限
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
#防止数据被篡改，进行锁表
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
#查看主数据库的状态信息
mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000002 | 878 | | | |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)16.从数据库的配置
#获得远程主机master主机的公钥
[root@slave ~]# mysql -h192.168.2.38 -uslave --get-server-public-key -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, 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.
#退出登录
mysql> quit
Bye
#启动mysql服务
[root@slave ~]# service mysql8 start
Starting MySQL SUCCESS!
#登录本地的slave服务器数据库
[root@slave ~]# mysql -pHui@2003
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 9
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, 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> change master to
-> master_host='192.168.2.38',
-> master_user='slave',
-> master_password='slave_123;',
-> master_port=3306,
-> master_log_file='binlog.000002',
-> master_log_pos=878;
Query OK, 0 rows affected, 9 warnings (0.03 sec)
#启动slave服务
mysql> start slave;
Query OK, 0 rows affected, 1 warning (0.02 sec)
#查看从服务器状态信息
mysql> show slave status\GSlave_IO_Running和Slave_SQL_Running都是yes就表示主从数据库配置成功了
二、进行主从数据同步测试
（1）主数据库
#在主数据库上创建表，插入数据
#创建不了，是因为锁表
mysql> create database test;
ERROR 1223 (HY000): Can't execute the query because you have a conflicting read lock
#解锁
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
#创建库
mysql> create database test;
Query OK, 1 row affected (0.01 sec)
#使用数据库
mysql> use test;
Database changed
#创建student表
mysql> create table student(id int primary key,name varchar(45) not null,gender varchar(4) not null);
Query OK, 0 rows affected (0.02 sec)
#插入数据
mysql> insert into student values(1,'张三'，'男');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '，'男')' at line 1
mysql> insert into student values(1,'张三','男');
Query OK, 1 row affected (0.03 sec)
mysql> insert into student values(2,'李四','男');
Query OK, 1 row affected (0.00 sec)
mysql> insert into student values(3,'王五','男');
Query OK, 1 row affected (0.00 sec)
mysql> insert into student values(4,'小凤仙','女');
Query OK, 1 row affected (0.00 sec)
#查看表中的数据
mysql> select * from student;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+----+-----------+--------+
4 rows in set (0.00 sec)（2）从数据库
#在从数据库上查看有没有同步主的数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.01 sec)
#使用test数据库
mysql> use test;
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
#可以看到数据已经同步过来了
mysql> select * from student;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+----+-----------+--------+
4 rows in set (0.01 sec)
可以看到数据都同步过来了四、mysql语句的增删改查
MySQL语句
1.新增
insert into库名称.表名
(id,username,password) values(1,"abc","123")
insert into 表名称 values(1,"name","word")
insert into 表名称 select * from 其他表
insert into 表 value () ,()
2.删除
delete from 表名
delete from tablename where id=3
delete from tablename where age>8
delete from tablename where name on ("a","b","c");
3.修改
update mysql.user set host='%' where name='root'
update user set password='abc' where username="hui"
4.查询
select
练习
查询
mysql> use test;
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> select name from student;
+-----------+
| name |
+-----------+
| 张三 |
| 李四 |
| 王五 |
| 小凤仙 |
+-----------+
4 rows in set (0.00 sec)
mysql> select id,gender from student;
+----+--------+
| id | gender |
+----+--------+
| 1 | 男 |
| 2 | 男 |
| 3 | 男 |
| 4 | 女 |
+----+--------+
4 rows in set (0.00 sec)
mysql> select a.*,b.* from student as a,student as b;
+----+-----------+--------+----+-----------+--------+
| id | name | gender | id | name | gender |
+----+-----------+--------+----+-----------+--------+
| 4 | 小凤仙 | 女 | 1 | 张三 | 男 |
| 3 | 王五 | 男 | 1 | 张三 | 男 |
| 2 | 李四 | 男 | 1 | 张三 | 男 |
| 1 | 张三 | 男 | 1 | 张三 | 男 |
| 4 | 小凤仙 | 女 | 2 | 李四 | 男 |
| 3 | 王五 | 男 | 2 | 李四 | 男 |
| 2 | 李四 | 男 | 2 | 李四 | 男 |
| 1 | 张三 | 男 | 2 | 李四 | 男 |
| 4 | 小凤仙 | 女 | 3 | 王五 | 男 |
| 3 | 王五 | 男 | 3 | 王五 | 男 |
| 2 | 李四 | 男 | 3 | 王五 | 男 |
| 1 | 张三 | 男 | 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 | 4 | 小凤仙 | 女 |
| 3 | 王五 | 男 | 4 | 小凤仙 | 女 |
| 2 | 李四 | 男 | 4 | 小凤仙 | 女 |
| 1 | 张三 | 男 | 4 | 小凤仙 | 女 |
+----+-----------+--------+----+-----------+--------+
16 rows in set (0.00 sec)创建可以远程登录的用户
mysql> create user 'haha'@'%' identified by 'Hui22003；'；
Query OK, 0 rows affected (0.00 sec)
mysql> grant all privileges on *.* to 'haha'@'%' ;
Query OK, 0 rows affected (0.01 sec)远程登录：
统计
# 用来统计的，这三个没区别
mysql> select count(*) from student;
+----------+
| count(*) |
+----------+
| 4 |
+----------+
1 row in set (0.07 sec)
mysql> select count(1) from student;
+----------+
| count(1) |
+----------+
| 4 |
+----------+
1 row in set (0.06 sec)
mysql> select count(gender) from student;
+---------------+
| count(gender) |
+---------------+
| 4 |
+---------------+
1 row in set (0.05 sec)别名
mysql> select id,name,gender from student;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+----+-----------+--------+
4 rows in set (0.00 sec)
mysql> select id as 编号,name,gender from student;
+--------+-----------+--------+
| 编号 | name | gender |
+--------+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+--------+-----------+--------+
4 rows in set (0.00 sec)
mysql> select id as 编号,name as 姓名,gender as 性别 from student;
+--------+-----------+--------+
| 编号 | 姓名 | 性别 |
+--------+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+--------+-----------+--------+
4 rows in set (0.00 sec)数据分析的基础
1.排序
1.max
2.min
2.汇总
1.count
2.sum
3.avg
练习
排序
mysql> select * from student;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+----+-----------+--------+
4 rows in set (0.00 sec)
按照性别排序
mysql> select * from student order by gender;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 4 | 小凤仙 | 女 |
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
+----+-----------+--------+
4 rows in set (0.00 sec)
按照性别进行降序/升序排序
mysql> select * from student order by gender desc;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
| 4 | 小凤仙 | 女 |
+----+-----------+--------+
4 rows in set (0.00 sec)
mysql> select * from student order by gender asc;
+----+-----------+--------+
| id | name | gender |
+----+-----------+--------+
| 4 | 小凤仙 | 女 |
| 1 | 张三 | 男 |
| 2 | 李四 | 男 |
| 3 | 王五 | 男 |
+----+-----------+--------+
4 rows in set (0.00 sec)新建一个表
mysql> create table product(
-> id int primary key auto_increment,
-> name varchar(45) not null,
-> price float not null,
-> qty int not null);
Query OK, 0 rows affected (0.03 sec)查看表的内容
mysql> desc product;
+-------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+----------------+
| id | int | NO | PRI | NULL | auto_increment |
| name | varchar(45) | NO | | NULL | |
| price | float | NO | | NULL | |
| qty | int | NO | | NULL | |
+-------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)插入数据
mysql> insert into product (name,price,qty) values("香蕉",8.5,200) ;
Query OK, 1 row affected (0.01 sec)
mysql> insert into product (name,price,qty) values("苹果",12.5,400) ;
Query OK, 1 row affected (0.00 sec)
mysql> insert into product (name,price,qty) values("菠萝",12.4,70) ;
Query OK, 1 row affected (0.00 sec)
mysql> insert into product (name,price,qty) values("哈密瓜",18.3,400) ;
Query OK, 1 row affected (0.00 sec)查看表
mysql> select * from product;
+----+-----------+-------+-----+
| id | name | price | qty |
+----+-----------+-------+-----+
| 1 | 香蕉 | 8.5 | 200 |
| 2 | 苹果 | 12.5 | 400 |
| 3 | 菠萝 | 12.4 | 70 |
| 4 | 哈密瓜 | 18.3 | 400 |
+----+-----------+-------+-----+
4 rows in set (0.00 sec)查看升序排列的qty
mysql> select * from product order by qty;
+----+-----------+-------+-----+
| id | name | price | qty |
+----+-----------+-------+-----+
| 3 | 菠萝 | 12.4 | 70 |
| 1 | 香蕉 | 8.5 | 200 |
| 2 | 苹果 | 12.5 | 400 |
| 4 | 哈密瓜 | 18.3 | 400 |
+----+-----------+-------+-----+
4 rows in set (0.00 sec)查看升序排列的价格
mysql> select * from product order by price;
+----+-----------+-------+-----+
| id | name | price | qty |
+----+-----------+-------+-----+
| 1 | 香蕉 | 8.5 | 200 |
| 3 | 菠萝 | 12.4 | 70 |
| 2 | 苹果 | 12.5 | 400 |
| 4 | 哈密瓜 | 18.3 | 400 |
+----+-----------+-------+-----+
4 rows in set (0.00 sec)先查看按照升序排列的qty，然后在这基础上在按照price的升序排列进行查看
mysql> select * from (select * from product order by qty ) as a order by a.price;
+----+-----------+-------+-----+
| id | name | price | qty |
+----+-----------+-------+-----+
| 1 | 香蕉 | 8.5 | 200 |
| 3 | 菠萝 | 12.4 | 70 |
| 2 | 苹果 | 12.5 | 400 |
| 4 | 哈密瓜 | 18.3 | 400 |
+----+-----------+-------+-----+
4 rows in set (0.00 sec)当使用聚合查询以后，不能使用where，如果要使用，添加having
聚合查询
练习
统计有多少男生和多少女生
mysql> select gender,count(gender) from student group by gender;
+--------+---------------+
| gender | count(gender) |
+--------+---------------+
| 男 | 3 |
| 女 | 1 |
+--------+---------------+
2 rows in set (0.00 sec)写别名
mysql> select gender as 性别,count(gender) as 人数 from student group by gender;
+--------+--------+
| 性别 | 人数 |
+--------+--------+
| 男 | 3 |
| 女 | 1 |
+--------+--------+
2 rows in set (0.00 sec)查看最大值、最小值、求和、求平均数
mysql> select max(price) from product;
+------------+
| max(price) |
+------------+
| 18.3 |
+------------+
1 row in set (0.00 sec)
mysql> select min(price) from product;
+------------+
| min(price) |
+------------+
| 8.5 |
+------------+
1 row in set (0.00 sec)
mysql> select sum(price) from product;
+-------------------+
| sum(price) |
+-------------------+
| 51.69999885559082 |
+-------------------+
1 row in set (0.00 sec)
mysql> select avg(price) from product;
+--------------------+
| avg(price) |
+--------------------+
| 12.924999713897705 |
+--------------------+
1 row in set (0.00 sec)
日期
mysql> select year('1985-7-6') as birth;
+-------+
| birth |
+-------+
| 1985 |
+-------+
1 row in set (0.00 sec)
mysql> select month('1985-7-6') as birth;
+-------+
| birth |
+-------+
| 7 |
+-------+
1 row in set (0.00 sec)
mysql> select month('1985-7-6') as mon;
+------+
| mon |
+------+
| 7 |
+------+
1 row in set (0.00 sec)now-显示现在的时间
mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2024-08-07 15:30:36 |
+---------------------+
1 row in set (0.00 sec)
mysql> select year(now());
+-------------+
| year(now()) |
+-------------+
| 2024 |
+-------------+
1 row in set (0.00 sec)
mysql> select second(now());
+---------------+
| second(now()) |
+---------------+
| 59 |
+---------------+
1 row in set (0.00 sec)
mysql> insert into product (name,price,qty) values(now(),7.8,90);
Query OK, 1 row affected (0.02 sec)
mysql> select * from product;
+----+---------------------+-------+-----+
| id | name | price | qty |
+----+---------------------+-------+-----+
| 1 | 香蕉 | 8.5 | 200 |
| 2 | 苹果 | 12.5 | 400 |
| 3 | 菠萝 | 12.4 | 70 |
| 4 | 哈密瓜 | 18.3 | 400 |
| 5 | 2024-08-07 15:32:48 | 7.8 | 90 |
+----+---------------------+-------+-----+
5 rows in set (0.00 sec)分组查询
mysql> select gender,count(gender) from student group by gender;
+--------+---------------+
| gender | count(gender) |
+--------+---------------+
| 男 | 3 |
| 女 | 1 |
+--------+---------------+
2 rows in set (0.00 sec)
mysql> select gender as 性别,count(gender) as 人数 from student group by gender;
+--------+--------+
| 性别 | 人数 |
+--------+--------+
| 男 | 3 |
| 女 | 1 |
+--------+--------+
2 rows in set (0.00 sec)子句查询
mysql> select sum(tt) from (select *,price*qty as tt from product) as a;
+--------------------+
| sum(tt) |
+--------------------+
| 14887.999668121338 |
+--------------------+
1 row in set (0.00 sec)向下取整
mysql> select trim("a b");
+-------------+
| trim("a b") |
+-------------+
| a b |
+-------------+
1 row in set (0.00 sec)
mysql> select floor(3.14);
+-------------+
| floor(3.14) |
+-------------+
| 3 |
+-------------+
1 row in set (0.00 sec)
mysql> select floor(-3.14);
+--------------+
| floor(-3.14) |
+--------------+
| -4 |
+--------------+
1 row in set (0.00 sec)向上取整
mysql> select ceiling(9.8);
+--------------+
| ceiling(9.8) |
+--------------+
| 10 |
+--------------+
1 row in set (0.00 sec)
mysql> select ceiling(9.3);
+--------------+
| ceiling(9.3) |
+--------------+
| 10 |
+--------------+
1 row in set (0.00 sec)四舍五入
mysql> select round(9.3);
+------------+
| round(9.3) |
+------------+
| 9 |
+------------+
1 row in set (0.00 sec)
mysql> select round(9.5);
+------------+
| round(9.5) |
+------------+
| 10 |
+------------+
1 row in set (0.00 sec)
