linux centos 7.5 安装mysql5.7
1 下载tar包，这里使用wget从官网下载（注：下载地址随时可能有变动，wget命令默认下载目录为当前所在文件夹）
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz
2 将mysql安装到/usr/local/mysql下
# 解压
tar -xvf mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz
# 移动
mv mysql-5.7.22-linux-glibc2.12-x86_64 /usr/local
# 重命名
mv /usr/local/mysql-5.7.22-linux-glibc2.12-x86_64 /usr/local/mysql
3 新建data目录
mkdir /usr/local/mysql/data
4、新建mysql用户、mysql用户组
# mysql用户组
groupadd mysql
# mysql用户
useradd mysql -g mysql
5 将/usr/local/mysql的所有者及所属组改为mysql
chown -R mysql.mysql /usr/local/mysql
6、配置，运行以下命令（注：使用下面命令如果出现错误，/usr/local/mysql/data 路径下有时候也会生成文件，然后换命令执行会提示错误，说data目录下有文件，删除data目录下的文件，再执行命令，总结:执行下面命令的时候，要保证
/usr/local/mysql/data 目录下没有文件）
/usr/local/mysql/bin/mysql_install_db --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data
# 如果出现以下错误：
2018-07-14 06:40:32 [WARNING] mysql_install_db is deprecated. Please consider switching to mysqld --initialize 2018-07-14 06:40:32 [ERROR] Child process: /usr/local/mysql/bin/mysqldterminated prematurely with errno= 32 2018-07-14 06:40:32 [ERROR] Failed to execute /usr/local/mysql/bin/mysqld --bootstrap --datadir=/usr/local/mysql/data --lc-messages-dir=/usr/local/mysql/share --lc-messages=en_US --basedir=/usr/local/mysql -- server log begin -- -- server log end --
# 则使用以下命令：
/usr/local/mysql/bin/mysqld --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data --initialize
# 如果出现以下错误：
/usr/local/mysql/bin/mysqld: error while loading shared libraries: libnuma.so.1: cannot open shared object file: No such file or directory
# 则执行以下命令：
yum -y install numactl
# 完成后继续安装：下面这条命令如果执行报错，可以忽略不执行
/usr/local/mysql/bin/mysqld --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data --initialize
# 编辑/etc/my.cnf
[mysqld] datadir=/usr/local/mysql/data basedir=/usr/local/mysql socket=/tmp/mysql.sock user=mysql port=3306 character-set-server=utf8 # 取消密码验证 skip-grant-tables # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 # skip-grant-tables [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid
7、开启服务
# 将mysql加入服务
cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql
# 开机自启
chkconfig mysql on
# 开启
service mysql start
(注：使用此命令可能报下面的错误，原因是权限不足和没有对应的文件，解决办法：https://blog.csdn.net/liukai6/article/details/78481308
楼主使用了下面的三条命令，依次执行，解决了这个问题：
mkdir /var/log/mariadb
touch /var/log/mariadb/mariadb.log
chown -R mysql:mysql /var/log/mariadb/
)
mysqld_safe error: log-error set to '/var/log/mariadb/mariadb.log', however file don't exists. Create writable for user 'mysql'.
8、设置密码
# 登录（由于/etc/my.cnf中设置了取消密码验证，所以此处密码任意）
/usr/local/mysql/bin/mysql -u root -p
# 操作mysql数据库
>>use mysql;
# 修改密码
>>update user set authentication_string=password('你的密码') where user='root';
>>flush privileges;
>>exit;
9、将/etc/my.cnf中的skip-grant-tables删除
10、登录再次设置密码（不知道为啥如果不再次设置密码就操作不了数据库了）
/usr/local/mysql/bin/mysql -u root -p
>>ALTER USER 'root'@'localhost' IDENTIFIED BY '修改后的密码';
>>exit;
11、允许远程连接
/usr/local/mysql/bin/mysql -u root -p
>>use mysql;
>>update user set host='%' where user = 'root';
>>flush privileges;
>>exit;
