问题:
1.遇到不输入密码能登上 ,使用密码报错.
2.(解压版的) 在cmd输入>mysql –u root –p 时，按enter回车时，会叫你输入密码
Enter password____,否则出现错误：
ERROR 1045(28000):Access denied for user’root’@’localhost’(using password:YES) 或者是 (using password:NO）

解决操作:
1.我们的先找到安装目录下的 my.ini文件.
2.编辑my.ini文件，在里面的[mysqld]条目下加上 skip-grant-tables,保存 .
3.以管理员权限运行cmd,停止mysql服务(安装版 的默认名mysql57 版本不一样有的是mysql56)，
输入:net stop mysql
再启动,输入net start mysql
(没配置好path的要找到bin目录下才输入)
4.输入:mysql –u root –p回车 .
5.进入到Enter password___ //这时可以直接按 enter键回车跳过.
6.此时我们进入了mysql数据库(但权限很低)
执行:Mysql>use mysql;
7.给root用户设置新密码  (下面的一句和网上的一些方法不一样,注意.)
执行:Mysql>update user set password=password(‘这里是你要的密码,自己输入用英文输入法的单引号括住‘)where user=‘root‘;
8.刷新数据库 Mysql>flush privileges;
9.退出mysql Mysql>quit;
10.这时重启服务就可以了(当然，别忘了先删除my.ini里面的skip-grant-tables)
11.上面修改后登陆后有问题看下面.

实例:
红色字体是要用到的语句,蓝色字体自己输入.
mysql> use mysql;
Database changed
mysql> UPDATE user SET Password=PASSWORD(‘root‘) where USER=‘root‘;
ERROR 1054 (42S22): Unknown column ‘Password‘ in ‘field list‘
mysql> update mysql.user set authentication_string=password(‘123qwe‘) where user=‘root‘ and Host=‘localhost‘;
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1

mysql> flush privilages;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near ‘privilages‘ at line 1
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> quit;
Bye

D:\Mysql\mysql-5.7.16-winx64\bin>mysql -uroot -p123qwe; (这个时候这样输入会报错)
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user ‘root‘@‘localhost‘ (using password: YES)

D:\Mysql\mysql-5.7.16-winx64\bin>mysql -uroot -p
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.16

Copyright (c) 2000, 2016, 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>

登陆后如果不能执行任何语句
报错:
You must reset your password using ALTER USER statement before executing this statement.

安装完mysql 之后，登陆以后，不管运行任何命令，总是提示上面错误语句,就在登录后,
以此执行下面语句(红色字体自己输入最好,因为标点格式可能不对)

1: SET PASSWORD = PASSWORD(‘your new password‘);

2: ALTER USER ‘root‘@‘localhost‘ PASSWORD EXPIRE NEVER;

3: flush privileges;

完成以上三步退出再登，使用新设置的密码(就是括号里的your new password)就行了.

MySQL安装使用的2个问题