最好把错误日志、/var/log/message系统日志(centos、redhat是这个问题件),贴上来看看,也有可能是没有mysqld文件,安装如下试试(这是我在centos下遇到的一个问题)
[root@mysql ~]# service mysqld start
Starting MySQL.2019-05-07T03:08:57.043405Z mysqld_safe Directory '/var/run/mysqld' for UNIX socket file don't exists.
ERROR! The server quit without updating PID file (/mysql/data/mysql.pid).
[root@mysql ~]# mkdir /var/run/mysqld
[root@mysql ~]# chown mysql.mysql /var/run/mysqld
[root@mysql ~]# service mysqld start
Starting MySQL...... SUCCESS!