完全卸載篇
一、使用以下命令查看當前安裝mysql情況，查找以前是否裝有mysql
rpm -qa|grep -i mysql
顯示之前安裝了：
MySQL-client-5.5.25a-1.rhel5
MySQL-server-5.5.25a-1.rhel5
2、停止mysql服務、刪除之前安裝的mysql
刪除命令：rpm -e –nodeps 包名
rpm -ev MySQL-client-5.5.25a-1.rhel5
rpm -ev MySQL-server-5.5.25a-1.rhel5
如果提示依賴包錯誤，則使用以下命令嘗試
rpm -ev MySQL-client-5.5.25a-1.rhel5 --nodeps
如果提示錯誤：error: %preun(xxxxxx) scriptlet failed, exit status
則用以下命令嘗試：
rpm -e --noscripts MySQL-client-5.5.25a-1.rhel5
3、查找之前老版本mysql的目錄、並且刪除老版本mysql的文件和庫
find / -name mysql
查找結果如下：
find / -name mysql
/var/lib/mysql
/var/lib/mysql/mysql
/usr/lib64/mysql
刪除對應的mysql目錄
rm -rf /var/lib/mysql
rm -rf /var/lib/mysql
rm -rf /usr/lib64/mysql
注意：卸載後/etc/my.cnf不會刪除，需要進行手工刪除
rm -rf /etc/my.cnf
4、再次查找機器是否安裝mysql
rpm -qa|grep -i mysql
安裝篇
1、下載tar包，這裏使用wget從官網下載
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.24-linux-glibc2.12-x86_64.tar.gz
2、將mysql安裝到/usr/local/mysql下
解壓
tar -xvf mysql-5.7.24-linux-glibc2.12-x86_64.tar.gz
移動
mv mysql-5.7.24-linux-glibc2.12-x86_64 /usr/local/
重命名
mv /usr/local/mysql-5.7.24-linux-glibc2.12-x86_64 /usr/local/mysql
3、新建data目錄
mkdir /usr/local/mysql/data
4、新建mysql用戶、mysql用戶組
mysql用戶組
groupadd mysql
mysql用戶
useradd mysql -g mysql
5、將/usr/local/mysql的所有者及所屬組改爲mysql
chown -R mysql.mysql /usr/local/mysql
6、配置
/usr/local/mysql/bin/mysql_install_db --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data
1，如果出現以下錯誤：
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 --
則使用以下命令：
/usr/local/mysql/bin/mysqld --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data --initialize
2，如果出現以下錯誤：
/usr/local/mysql/bin/mysqld: error while loading shared libraries: libnuma.so.1: cannot open shared object file: No such file or directory
然後則執行以下命令：
yum -y install numactl
完成後繼續安裝：
/usr/local/mysql/bin/mysqld --user=mysql --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/data --initialize
解決問題後
編輯/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
# 取消密碼驗證
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、開啓服務
將mysql加入服務
cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql
開機自啓
chkconfig mysql on
開啓服務
service mysql start
8、設置密碼
登錄（由於/etc/my.cnf中設置了取消密碼驗證，所以此處密碼任意）
/usr/local/mysql/bin/mysql -u root -p
操作mysql數據庫
>>use mysql;
修改密碼
>>update user set authentication_string=password('你的密碼') where user='root';
>>flush privileges;
>>exit;
9、將/etc/my.cnf中的skip-grant-tables刪除
10、登錄再次設置密碼（不知道爲啥如果不再次設置密碼就操作不了數據庫了）
/usr/local/mysql/bin/mysql -u root -p
>>ALTER USER 'root'@'localhost' IDENTIFIED BY '修改後的密碼';
>>exit;
11、允許遠程連接
/usr/local/mysql/bin/mysql -u root -p
>>use mysql;
>>update user set host='%' where user = 'root';
>>flush privileges;
>>eixt;
12、添加快捷方式（軟連接）
ln -s /usr/local/mysql/bin/mysql /usr/bin
參考：https://www.cnblogs.com/nicknailo/articles/8563456.html
https://www.cnblogs.com/daemon-/p/9009360.html