本次mysql数据库安装采用二进制安装(免安装即绿色版)，数据库版本是mysql5.7.26
首先下载mysql安装包，然后上传服务器里，最后解压。
卸载centos7自带的数据库软件包：
[root@localhost mysql]# yum remove mariadb
开始安装mysql:
[root@localhost tools]# ll
total 629756
-rw-r–r– 1 root root 644869837 Dec 11 15:35 mysql-5.7.26-linux-glibc2.12-x86_64.tar.gz
[root@localhost tools]# tar xf mysql-5.7.26-linux-glibc2.12-x86_64.tar.gz
[root@localhost tools]# mv mysql-5.7.26-linux-glibc2.12-x86_64 /application/mysql
[root@localhost ~]# useradd -s /sbin/nologin mysql
把如下内容太添加到/etc/profile末尾行，然后执行命令使生效：
export PATH=/application/mysql/bin:$PATH
[root@localhost ~]# source /etc/profile
查看是否生效，使用命令查看Mysql版本：
[root@localhost ~]# mysql -V
mysql Ver 14.14 Distrib 5.7.26, for linux-glibc2.12 (x86_64) using EditLine wrapper
授权：
[root@localhost ~]# chown -R mysql.mysql /application/*
[root@localhost ~]# chown -R mysql.mysql /data
初始化数据方式一：密码设置比较复杂
创建mysql数据目录：
[root@localhost ~]# mkdir /data/mysql/data -p
[root@localhost ~]# chown -R mysql.mysql /data
注意：mysql错误日志默认在数据目录里，默认是主机名.err！！！
[root@localhost ~]# mysqld –initialize –user=mysql –basedir=/application/mysql –datadir=/data/mysql/data
2019-12-12T02:09:08.794620Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use –explicit_defaults_for_timestamp server option (see documentation for more details).
2019-12-12T02:09:12.036238Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-12-12T02:09:12.283068Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-12-12T02:09:12.346261Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 63c6e908-1c84-11ea-9a0c-000c29002b3d.
2019-12-12T02:09:12.693297Z 0 [Warning] Gtid table is not ready to be used. Table ‘mysql.gtid_executed’ cannot be opened.
2019-12-12T02:09:12.697614Z 1 [Note] A temporary password is generated for root@localhost: #vVZul3CIt_f
初始化数据方式二：密码设置简便
[root@localhost ~]# rm -rf /data/mysql/data/*
[root@localhost ~]# mysqld –initialize-insecure –user=mysql –basedir=/application/mysql –datadir=/data/mysql/data
2019-12-12T03:04:10.776764Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use –explicit_defaults_for_timestamp server option (see documentation for more details).
2019-12-12T03:04:12.401550Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-12-12T03:04:12.571184Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-12-12T03:04:12.637140Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 12e75191-1c8c-11ea-a008-000c29002b3d.
2019-12-12T03:04:12.640047Z 0 [Warning] Gtid table is not ready to be used. Table ‘mysql.gtid_executed’ cannot be opened.
2019-12-12T03:04:12.643946Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the –initialize-insecure option.
配置mysql配置文件：
[root@localhost data]# cp /etc/my.cnf /tmp/my.cnf20191212bak
[root@localhost data]# >/etc/my.cnf
[root@localhost data]# cat >> /etc/my.cnf<< EOF
[mysqld]
user=mysql
basedir=/application/mysql
datadir=/data/mysql/data
socket=/tmp/mysql.sock
server_id=6
port=3306
[mysql]
socket=/tmp/mysql.sock
> EOF
启动mysql数据库：centos7启动mysql数据库有两种方式
方式1：
[root@localhost ~]# cp /application/mysql/support-files/mysql.server /etc/init.d/mysqld
[root@localhost ~]# service mysqld status
ERROR! MySQL is not running
[root@localhost ~]# service mysqld start
Starting MySQL.Logging to ‘/data/mysql/data/localhost.localdomain.err’.
. SUCCESS!
方式2：编辑如下配置文件
[root@localhost ~]# more /usr/lib/systemd/system/mysqld.service
[Unit]
Description=MySQL Server
Documentation=man:mysqld(8)
Documentation=http://dev.mysql.com/doc/refman/en/using-systemd.html
After=network.target
After=syslog.target
[Install]
WantedBy=multi-user.target
[Service]
User=mysql
Group=mysql
ExecStart=/application/mysql/bin/mysqld –defaults-file=/etc/my.cnf
启动mysql:
[root@localhost ~]# systemctl start mysqld.service
[root@localhost ~]# netstat -lnp |grep 3306
tcp6 0 0 :::3306 :::* LISTEN 25994/mysqld
如何修改mysql 管理员（root）用户密码：
[root@localhost ~]# mysqladmin -uroot -p password xxxxxxxxxx
然后直接回车就OK了！
