1.为了安全期间，首先需要备份原有数据

2.卸载原有MySQL，先停止原有的MySQL服务，再查找 find / -name mysql

[root@qxyw /]# find / -name mysql/var/lib/mysql/var/lib/mysql/mysql/usr/lib64/mysql

并移除服务

[root@qxyw /]# rm -rf /var/lib/mysql[root@qxyw/]# rm -rf /usr/lib64/mysql

3.安装cmake

[root@qxyw download]# wget http://www.cmake.org/files/v2.8/cmake-2.8.12.2.tar.gz
[root@qxyw download]# tar -xzvf cmake-2.8.12.2.tar.gz
[root@qxyw download]# cd cmake-2.8.12.2[root@qxyw cmake-2.8.12.2]# ./configure
[root@qxyw cmake-2.8.12.2]# make && make install

4.下载安装MySQL5.5.36

[root@qxyw download]# wget http://dev.mysql.com/get/Downloads/MySQL-5.5/mysql-5.5.36.tar.gz
[root@qxyw download]# tar xzvf mysql-5.5.36.tar.gz
[root@qxyw download]# cd mysql-5.5.36[root@qxyw mysql-5.5.36]# cmake -DCMAKE_INSTALL_PREFIX=/usr/local/mysql -DEXTRA_CHARSETS=all -DDEFAULT_CHARSET=utf8 -DDEFAULT_COLLATION=utf8_general_ci -DWITH_READLINE=1 -DWITH_SSL=system -DWITH_ZLIB=system -DWITH_EMBEDDED_SERVER=1 -DENABLED_LOCAL_INFILE=1 -DMYSQL_DATADIR=/home/mysql
[root@qxyw mysql-5.5.36]# make && make install

在cmake的过程中出错了，提示Could NOT find Curses (missing:  CURSES_LIBRARY CURSES_INCLUDE_PATH)

执行以下代码就可以了，执行好之后继续cmake，然后再make && make install

[root@localhost mysql-5.5.36]# rmCMakeCache.txt
[root@localhost mysql-5.5.36]# yum install ncurses-devel

5.接下来需要把之前备份下来的my.cnf文件，复制至/etc/my.cnf
MySQL会读取/etc/my.cnf /etc/mysql/my.cnf /usr/local/mysql/etc/my.cnf /.my.cnf。左边的文件优先级是最高的

6.配置好之后，我们就启动mysql，发现有一个问题启动MySQL提示:The server quit without updating PID file(…)失败
查看my.cnf文件设置的日记文件地址/var/log/mysqld.log，错误提示如下

170715 12:31:36 mysqld_safe mysqld from pid file /var/lib/mysql/qxyw.pid ended170715 12:57:48 mysqld_safe Starting mysqld daemon with databases from /home/mysql170715 12:57:48InnoDB: The InnoDB memory heap is disabled170715 12:57:48InnoDB: Mutexes and rw_locks use GCC atomic builtins170715 12:57:48 InnoDB: Compressed tables use zlib 1.2.3
170715 12:57:48 InnoDB: Initializing buffer pool, size = 128.0M
170715 12:57:48InnoDB: Completed initialization of buffer pool170715 12:57:48 InnoDB: highest supported fileformat is Barracuda.170715 12:57:48  InnoDB: Waiting forthe background threads to start170715 12:57:49 InnoDB: 5.5.36 started; log sequence number 2645823
170715 12:57:49 [ERROR] /usr/local/mysql/bin/mysqld: unknown variable 'default-character-set=utf8'170715 12:57:49 [ERROR] Aborting

此报错是由/etc/my.cnf配置文件下的[mysqld]设置字符集引起的，解决方法：将default-character-set=utf8 改为 character_set_server=utf8

7.通过mysql -u root -p命令连接mysql。（我们之前有安装过mysql，数据库文件还在，所以不需要再添加用户设置权限了）
出现了错误信息：ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'

出错原因是我们mysql.sock文件在/usr/lib/mysql/文件夹下
可以尝试通过下面命令连接，并查看mysql版本

[root@qxyw var]# mysql -u root -p -S /usr/lib/mysql/mysql.sockmysql> selectversion();+-----------+
| version() |
+-----------+
| 5.5.36    |
+-----------+
1 row in set (0.00 sec)