$ sudo yum install mysql55-mysql-server mysql55-mysql-client

...

$ rpm -qa | grep -i mysql              

mysql55-mysql-libs-5.5.45-1.el5

mysql-5.0.95-5.el5_9

mysql55-mysql-5.5.45-1.el5

mysql55-runtime-1-12.el5

mysql55-mysql-server-5.5.45-1.el5

perl-DBD-MySQL-3.0007-2.el5

$ sudo yum install MariaDB-server MariaDB-client

Loaded plugins: security

Setting up Install Process

Resolving Dependencies

--> Running transaction check

---> Package MariaDB-client.i386 0:10.1.13-1 set to be updated

--> Processing Dependency: MariaDB-common for package: MariaDB-client

---> Package MariaDB-server.i386 0:10.1.13-1 set to be updated

--> Processing Dependency: galera for package: MariaDB-server

--> Running transaction check

---> Package MariaDB-common.i386 0:10.1.13-1 set to be updated

---> Package galera.i386 0:25.3.15-1.rhel5.el5 set to be updated

--> Processing Conflict: mysql conflicts MySQL

--> Restarting Dependency Resolution with new changes.

--> Running transaction check

---> Package MariaDB-shared.i386 0:10.1.13-1 set to be updated

--> Processing Dependency: libmysqlclient.so.15 for package: perl-DBD-MySQL

--> Processing Dependency: libmysqlclient.so.15(libmysqlclient_15) for package: perl-DBD-MySQL

--> Running transaction check

---> Package MariaDB-compat.i386 0:10.1.13-1 set to be updated

--> Finished Dependency Resolution

Dependencies Resolved

=====================================================================================================================================

 Package                           Arch                    Version                                   Repository                 Size

=====================================================================================================================================

Installing:

 MariaDB-client                    i386                    10.1.13-1                                 local                      14 M

 MariaDB-server                    i386                    10.1.13-1                                 local                      66 M

 MariaDB-shared                    i386                    10.1.13-1                                 local                     1.6 M

     replacing  mysql.i386 5.0.95-5.el5_9

Installing for dependencies:

 MariaDB-common                    i386                    10.1.13-1                                 local                      50 k

 MariaDB-compat                    i386                    10.1.13-1                                 local                     3.3 M

 galera                            i386                    25.3.15-1.rhel5.el5                       galera                     11 M

Transaction Summary

=====================================================================================================================================

Install       6 Package(s)

Upgrade       0 Package(s)

  Erasing        : mysql                                                                                                         7/7 

Installed:

  MariaDB-client.i386 0:10.1.13-1             MariaDB-server.i386 0:10.1.13-1             MariaDB-shared.i386 0:10.1.13-1            

Dependency Installed:

  MariaDB-common.i386 0:10.1.13-1            MariaDB-compat.i386 0:10.1.13-1            galera.i386 0:25.3.15-1.rhel5.el5           

Replaced:

  mysql.i386 0:5.0.95-5.el5_9                                                                                                        

Complete!

$ rpm -qa | grep -iE 'mysql|maria'

mysql55-mysql-libs-5.5.45-1.el5

MariaDB-common-10.1.13-1

MariaDB-shared-10.1.13-1

mysql55-mysql-5.5.45-1.el5

MariaDB-compat-10.1.13-1

MariaDB-server-10.1.13-1

mysql55-runtime-1-12.el5

mysql55-mysql-server-5.5.45-1.el5

MariaDB-client-10.1.13-1

perl-DBD-MySQL-3.0007-2.el5

$ mysql -uroot -e "select @@version, @@version_comment"

+-----------+------------------------------+

| @@version | @@version_comment            |

+-----------+------------------------------+

| 5.5.45    | MySQL Community Server (GPL) |

+-----------+------------------------------+