Mysql5.7 安装问题

在/etc/my.cnf下 添加禁用密码加粗样式强度审计插件无法启动
validate-password=OFF #不使用密码强度审计插件
插入
plugin-load=validate_password.so

密码无法修改报错

ERROR 1558 (HY000): Column count of mysql.user is wrong. Expected 43, found 42. Created with MySQL 5

错误是卸载原有版本装完5.7之后没有更新数据库里面的结构信息导致的

mysql_upgrade -u root -p password

这个报错的解决方法
2019-06-21T09:14:20.556119Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-06-21T09:14:20.563296Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting.
2019-06-21T09:14:20.563368Z 0 [ERROR] Aborting

将 /var/lib/mysqld 删除或者mv移动改名备份
重新启动即可

没有临时密码怎么办
删除之前原有的mysql数据 /var/lib/mysql 重启mysql即可

rm -rf /var/lib/mysql
systemctl restart mysqld
grep 'password' /var/log/mysqld.log