【问题1】在centos6.8上使用yum直接安装MysqL，一切正常安装。启动MysqL时显示：
ERROR 2002 (HY000): Can’t connect to local MysqL server through socket ‘/var/lib/MysqL/MysqL.sock’ (2)
（1）、cp /usr/share/MysqL/my-medium.cnf/ /etc/my.cnf（将默认的配置文件模板复制过去覆盖原有的配置文件）；
（2）、/etc/init.d/MysqLd status查看MysqL运行状态，显示正常；
（3）、解决办法：
vim /etc/my.conf,在[MysqLd]下面加入一句话：
【现在直接输入MysqL直接进入MySQL命令窗口】
【问题2】不能用MysqL -u root -p 登录，显示：
ERROR 1045 (28000): Access denied for user 'mysql'@'localhost' (using password: NO)
解决办法：
在MysqL配置文件/etc/my.conf中的[MysqLd]中加入:
pid-file=/var/lib/MysqL/MysqLid.pid
原因：MysqL 用户没有操作/var/run目录的权限，所以pid文件无法创建，导致登陆时无法建立 进程信息文件，登陆进程就无法开启，自然无法登陆。
【问题3】刚刚装好的MysqL没有为root设置密码，直接输入MysqL就可以登录，为root设置密码的方法：
在linux命令行界面输入：
mys1qladmin-urootpassword'123'
再次用root身份登录：
mys1ql-uroot-p
【问题4】之前装好一个MysqL，但是由于忘记了root密码，于是把文件/application/MysqL删除了，然后重新解压一个MysqL文件到/application下，并按照步骤设好各种环境，但是打开MysqL是还是会有问题，显示：
[root@localhostsupport-files]#/etc/init.d/MysqLdstart
StartingMysqL...TheserverquitwithoutupdatingPIDfile[失败]ication/MysqL/data/localhost.localdomain.pid).
查看有关MysqL的进程
[root@localhostsupport-files]#ps-ef|grepMysqL
root 12821 1 0 May15 ? 00:00:00 /bin/sh /application/MysqL/bin/MysqLd_safe --datadir=/application/MysqL/data --pid-file=/application/MysqL/data/localhost.localdomain.pid
MysqL 12949 12821 0 May15 ? 00:00:14 /application/MysqL/bin/MysqLd --basedir=/application/MysqL --datadir=/application/MysqL/data --plugin-dir=/application/MysqL/lib/plugin --user=MysqL --log-error=/application/MysqL/data/localhost.localdomain.err --pid-file=/application/MysqL/data/localhost.localdomain.pid --socket=/tmp/MysqL.sock
root 18450 17925 0 10:10 pts/0 00:00:00 grep MysqL
杀死这两个进程
[root@localhostsupport-files]#kill-912821
[root@localhostsupport-files]#kill-912949
再次打开MysqL
[root@localhostsupport-files]#/etc/init.d/MysqLdstart
Starting MysqL.. [确定]
[root@localhostsupport-files]#MysqL
Welcome to the MysqL monitor. Commands end with ; or \g.
Your MysqL connection id is 1
Server version: 5.5.32 MysqL Community Server (GPL)
copyright (c) 2000,2013,Oracle and/or its affiliates. All rights reserved.
Oracle is a registered Trademark of Oracle Corporation and/or its
affiliates. Other names may be Trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MysqL> quit
Bye
【问题5】初始化数据库报错如下，执行
/application/mysql-5.6.36/scripts/MysqL_install_db --datadir=/application/mysql-5.6.36/data/ --basedir=/application/mysql-5.6.36/ --user=MysqL 时报以下错误：
-bash: /application/mysql-5.6.36/scripts/MysqL_install_db: /usr/bin/perl: bad interpreter: No such file or directory
【解决办法】
yum -y install perl perl-devel
【问题6】在问题5的基础上，安装好了perl，再次执行初始化数据库命令
/application/mysql-5.6.36/scripts/MysqL_install_db --datadir=/application/mysql-5.6.36/data/ --basedir=/application/mysql-5.6.36/ --user=MysqL 时报以下错误：
Fatal error: please install the following Perl modules before executing /application/mysql-5.6.36/scripts/MysqL_install_db:
【解决办法】
yum install -y perl-Module-Install.noarch
