mysql不能连接本机服务器
连接localhost，空密码，可以连接。
$ mysql -u root -h localhost -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4 to server version: 4.0.14-classic
Type ‘help; ‘ or ‘\h ‘ for help. Type ‘\c ‘ to clear the buffer.
mysql> quit
Bye
连接机器名sd03，空密码，出现错误。
$ mysql -u root -h sd03 -p
Enter password:
ERROR 2003: Can ‘t connect to MySQL server on ‘sd03 ‘ (239)
$
需要sd03上MySQL服务器的root用户名密码
本机的MySQL不需要密码，并不代表sd03上的也不需要密码
给sd03上MySQL服务器的root用户赋予网络连接的权限了吗？
GRANT ALL PRIVILEGES ON *.* TO root@ “% ” WITH GRANT OPTION;
$ mysql -u root -h localhost -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4 to server version: 4.0.14-classic
Type ‘help; ‘ or ‘\h ‘ for help. Type ‘\c ‘ to clear the buffer.
mysql> GRANT ALL PRIVILEGES ON *.* TO root@ “% ” WITH GRANT OPTION;
Query OK, 0 rows affected (0.04 sec)
mysql>
开了防火墙也会导致连接不到服务器
需要给机器赋予权限的，MySQL默认的是localhost！
新建一个用户来连接，或者给root用户授权可以进行网络连接
