小知识，大挑战！本文正在参与“程序员必备小知识”创作活动。
rpm -q查询结果中的包名和软件包自身的包名一致，比如MariaDB-server-10.3.18，因此查询和卸载MariaDB时，大小写要正确！，否则可能查询不到或不会执行卸载。
安装MySQL时，配置好仓库源，就可以执行 yum install -y mysql-community-server 直接安装了。
mysql的包名中就是用小写来表示的。
但是，如下，如果已经安装了MariaDB，就会与 mysql 产生冲突。产生类似 file xxx from install of xxx conflicts with file from package xxx 的冲突报错。
下面是mysql与MariaDB冲突的详细报错信息，可以看到对应的 MariaDB-xxx包名。
Running transaction check
Running transaction test
Transaction check error:
file /usr/bin/mysql from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqladmin from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqlbinlog from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqlcheck from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqldump from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqlimport from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqlshow from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqlslap from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysql.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqladmin.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqlbinlog.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqlcheck.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqldump.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqlimport.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqlshow.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqlslap.1.gz from install of mysql-community-client-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-client-10.3.18-1.el7.centos.x86_64
file /etc/my.cnf from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-common-5.5.63-1.el7.centos.x86_64
file /etc/logrotate.d/mysql from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/innochecksum from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/my_print_defaults from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/myisam_ftdump from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/myisamchk from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/myisamlog from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/myisampack from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysql_secure_installation from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysql_tzinfo_to_sql from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysql_upgrade from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/mysqldumpslow from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/bin/perror from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/lib64/mysql/plugin/auth_socket.so from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/sbin/mysqld from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/innochecksum.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/my_print_defaults.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/myisam_ftdump.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/myisamchk.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/myisamlog.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/myisampack.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysql_secure_installation.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysql_tzinfo_to_sql.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysql_upgrade.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/mysqldumpslow.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man1/perror.1.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
file /usr/share/man/man8/mysqld.8.gz from install of mysql-community-server-8.0.26-1.el7.x86_64 conflicts with file from package MariaDB-server-10.3.18-1.el7.centos.x86_64
Error Summary
-------------
卸载所有的MariaDB相关的软件：
for i in $(rpm -qa|grep MariaDB);do sudo rpm -e $i --nodeps;done
注意grep处 MariaDB 大写。MariaDB的软件包名是有大小写区别的，否则查询不到。
rpm的软件包名是区分大小写的，在查询、使用、安装时，都要对应正确的名称！
