MYSQL problems and how to solve them

1.ERROR 1045 (28000): Access denied for user ' root ' @ ' localhost ' (using Password:yes)

1) Turn off the MySQL service

/etc/init.d/mysqld stop

2) Enable Safe Mode & background operation

Mysqld_safe--user=mysql--skip-grant-tables--skip-networking &

3) Login

Mysql-u Root mysql

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Branch One:

4) Query User table

Mysql> select * from user;

5) Insert New user

mysql> INSERT INTO User (Password,user) VALUES (Password (' root '), ' root ');

Attention:

Insert into User (Password,user) VALUES (' 123 ', ' root '); No, because the secret must be encrypted with the Password () function.

mysql>quit;

Tip: The second time you execute an INSERT statement, the same root, password will prompt the following error message

mysql> INSERT INTO User (Password,user) VALUES (Password (' root '), ' root '), error 1062 (23000): Duplicate entry ' roo T ' for key ' PRIMARY '

Branch Two:

mysql> UPDATE user SET Password=password (' NewPassword ') where user= ' root ';

mysql> FLUSH privileges; Remember to say this, otherwise if you close the previous terminal, the original error will appear

Mysql> quit

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6) Restart MySQL service

/etc/init.d/mysqld start

7) Login

Mysql-u root-p

Enter Password: < Enter the new password newpassword>//is still a failure. Tip Error 1045 (28000); Reset the root password by UPDATE to 1234 instead of root, and then successfully landed
Mysql>

2.mysql_real_connect connection to database error:

about how to use Mysql_real_connect () to connect to a remote database

Http://www.cnitblog.com/guopingleee/archive/2009/02/14/54548.html

(GDB) P m_pszipaddress
$ = "localhost", ' \000 ' <repeats times>
(GDB) P M_pszusername
$ = "root", ' \000 ' <repeats times>
(GDB) P M_pszuserpassword
$ $ = "1234", ' \000 ' <repeats times>
(GDB) P M_pszdatabasename
$4 = "Mytestdb", ' \000 ' <repeats times>

If the second parameter

const char *host,//Connection host

Set to localhost, calling Mysql_real_connect can run successfully.

When you change to 192.168.1.100, the following error is reported:

$ = "Access denied for user ' root ' @ ' to database ' Mytestdb ', 42000", ' \000 ' <repeats 961 times>

After executing the following code, the error prompt changes to:

Mysql-u root-p

Enter password

Grant all privileges the on database name . * to ' root ' @ '% '; Database name such as: Mytestdb

$ = "Access denied for user ' root ' @ ' 192.168.88.131 ' (using Password:yes), 28000", ' \000 ' <repeats 948 times>

Do not know how to deploy MySQL database.

3.

Q: The following error occurred while logging on to MySQL on another machine:

ERROR 2003 (HY000): Can ' t connect to MySQL server on ' x.x.x.x ' (111)

A: Because MySQL takes security into account, the default configuration only lets you log on locally

Open the/etc/mysql/my.cnf file, locate bind-address = 127.0.0.1 modified to bind-address = 0.0.0.0///etc/mysql/my.cnf cannot find this file.

Restart mysql:sudo/etc/init.d/mysql Restart

Q: There is a situation similar to the following error:

ERROR 1045 (28000): Access denied for user ' test ' @ ' x.x.x.x ' (using Password:no)

A: The reason is that the logon user name is not set to the remote host logon permission.

Log in locally with root: Mysql-u root-p

Modify the Host field in the user table in the MySQL database to apply the user name, and change localhost to%

Use MySQL;

Update user Set Host = '% ' where user = ' username ';

MYSQL problems and how to solve them