本文介绍如何在centos-7下安装和卸载mysql8.0，并使用SQLyog客户端工具连接mysql.1。卸载MySQL1.1卸载mariadb检查mariadb：$rpm-qa|grepmariadb如果上面检查的结果有内容，删除Mariadb，将命令中的mariadb-server替换为以上所有输出内容：$rpm\-e--nodepsmariadb-server1.2卸载mysql并查看mysql:$rpm-qa|grepmysqlmysql80-community-release-el7-3.noarchmysql-community-libs-8.0.19-1.el7.x86_64mysql-community-server-8.0.19-1.el7.x86_64mysql-community-common-8.0.19-1.el7.x86_64mysql-community-client-8.0.19-1.el7.x86_64$systemctlstatusmysqldMysqld.service-MySQL服务器加载：加载（/usr/lib/systemd/system/mysqld.service；启用；供应商预设：禁用）活动：活动（运行）自星期六2020-04-0415:46:48CST；6天前文档：man:mysqld(8)http://dev.mysql.com/doc/refman/en/using-systemd.html主PID：9608(mysqld)状态：“服务器正在运行”CGroup：/system.slice/mysqld.service└─9608/usr/sbin/mysqld停止mysqld.service服务:$sudosystemctlstopmysqld删除mysql程序:$sudorpm-e--nodepsmysql80-community-release-el7-3.noarchmysql-community-libs-8.0.19-1.el7.x86_64mysql-community-server-8.0.19-1.el7.x86_64mysql-community-common-8.0.19-1.el7.x86_64mysql-community-client-8.0.19-1.el7.x86_64warning:/etc/my.cnf另存为/etc/my.cnf.rpmsave删除所有mysql相关文件：$sudorm-rf/var/lib/mysql/var/log/mysqld.log2。安装MySQL在CentOS-7中安装MySQL需要配置下载源，不能直接使用yum安装2.1添加MySQLYumRepository下载MySQL源官网地址：dev.mysql.com/downloads查看系统version:shell>cat/etc/redhat-releaseCentOSLinuxrelease7.6.1810(Core)选择对应的版本下载，比如CentOS7目前在官网查看最新的yum源的下载地址：dev。mysql.com/get/mysql80...shell>wgethttps://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpminstallMySQLsourceshell>sudorpm-Uvhplatform-and-version-specific-package-name.rpm例如CentOS7上最新的MySQL源码安装：shell>sudorpm-Uvhmysql80-community-release-el7-3.noarch.rpm查看是否安装成功执行成功后，会在/etc/yum.repos.d/目录下生成两个repo文件mysql-community.repo和mysql-community-source.repo通过yumrepolistshell查看mysql相关资源>yumr已启用epolist|grep"mysql.*-community.*"!mysql-connectors-community/x86_64MySQL连接器社区108!mysql-tools-community/x86_64MySQL工具社区90!mysql80-community/x86_64MySQL8.0社区服务器1132.2选择MySQL版本使用MySQLYumRepository安装MySQL，默认选择最新的稳定版。比如你通过上面的MySQL源安装，默认安装会选择MySQL8.0版本。如果你只想安装这个版本，可以直接跳过这一步。如果没有，比如我这里要安装MySQL5.7，需要“切换版本”：查看当前MySQLYumRepository中所有的MySQL版本（每个版本在不同的子仓库）shell>yumrepolist所有|grepmysqlswitchVersionshell>sudoyum-config-manager--disablemysql80-communityshell>sudoyum-config-manager--enablemysql57-community2.3安装MySQL安装：$sudoyuminstallmysql-community-server启动：$sudosystemctlstartmysqld查看状态：$sudosystemctlstatusmysqld2.4设置root密码我们自己测试用的root密码不需要太复杂。通过设置my.cnf，可以设置一个简单的密码（适用于mysql8.0）。设置好这些策略后，必须执行sudosystemctlrestartmysqld才能生效：validate_password.check_user_name=0validate_password.policy=0validate_password.mixed_case_count=0validate_password.number_count=0validate_password.special_char_count=0validate_password.length=0查看mysqlroot用户的密码：$sudogrep'temporarypassword'/var/log/mysqld.log2020-04-12T12:06:54.575[571ZNote][MY-010454][Server]为root@localhost生成一个临时密码：d%tcKY,VO6:o登录mysql:$mysql-uroot-p输入密码：欢迎使用MySQL监视器。命令以;结尾或\g。您的MySQL连接ID是8Server版本：8.0.19版权所有(c)2000、2020、Oracle和/或其附属公司。保留所有权利。Oracle是OracleCorporation和/或其附属公司的注册商标。其他名称可能是其各自所有者的商标。键入“帮助；”或'\h'寻求帮助。输入'\c'清除当前输入语句。mysql>修改默认root密码：mysql>ALTERUSER'root'@'localhost'IDENTIFIEDBY'root';QueryOK,0rowsaffected(0.01sec)查看密码策略：mysql>显示像'validate_password%'这样的变量；+------------------------------------+--------+|变量名|值|+--------------------------------------+------+|validate_password.check_user_name|关闭||验证密码.dictionary_file|||验证密码长度|0||validate_password.mixed_case_count|验证密码0||validate_password.number_count|验证密码0||validate_password.policy|低||验证密码.special_char_count|0|+--------------------------------------+--------+7rowsinset(0.00sec)2.5Allowremoteconnectiontosetpermissions,allowremoteconnectionrootusermysql>CREATEUSER'root'@'%'IDENTIFIEDBY'root';查询OK,0rowsaffected(0.01sec)mysql>使用GRANTOPTION将*.*上的所有权限授予'root'@'%'；查询正常，0行受影响（0.00秒）设置加密方法，SQLyog可以连接到mysql>ALTERUSER'root'@'%'IDENTIFIEDWITHmysql_native_passwordBY'root';查询正常，0行受影响（0.00秒）2.6打开3306端口$sudofirewall-cmd--zone=public--add-port=3306/tcp--eric的永久[sudo]密码：success$sudofirewall-cmd--list-ports$sudofirewall-cmd--reloadsuccess$sudofirewall-cmd--list-ports3306/tcp3。客户端SQLyog连接MySQL使用SQLyog连接mysql可以参考文档CentOS安装MySQL详解HowtograntallprivilegestorootuserinMySQL8.0SQLyogerror2058:connecttomysql8.0.11解决办法
