MySQL 5.0 Reference Manual  /  ...  /  Assigning Account Passwords

6.3.5 Assigning Account Passwords

Required credentials for clients that connect to the MySQL server can include a password. This section describes how to assign passwords for MySQL accounts.

MySQL stores passwords in the user table in the mysql database. Operations that assign or modify passwords are permitted only to users with the CREATE USER privilege, or, alternatively, privileges for the mysql database (INSERT to create new accounts, UPDATE to modify existing accounts).

To assign a password when you create a new account with CREATE USER, include an IDENTIFIED BY clause:

mysql> CREATE USER 'jeffrey'@'localhost'
    -> IDENTIFIED BY 'mypass';

To assign or change a password for an existing account, one way is to issue a SET PASSWORD statement:

    -> 'jeffrey'@'localhost' = PASSWORD('mypass');

If you are not connected as an anonymous user, you can change your own password by omitting the FOR clause:

mysql> SET PASSWORD = PASSWORD('mypass');

The old_passwords system variable value determines the hashing method used by PASSWORD(). If you specify the password using that function and SET PASSWORD rejects the password as not being in the correct format, it may be necessary to set old_passwords to change the hashing method. For descriptions of the permitted values, see Section 5.1.4, “Server System Variables”.

You can also use a GRANT USAGE statement at the global level (ON *.*) to assign a password to an account without affecting the account's current privileges:

mysql> GRANT USAGE ON *.* TO 'jeffrey'@'localhost'
    -> IDENTIFIED BY 'mypass';

To assign a password from the command line, use the mysqladmin command:

shell> mysqladmin -u user_name -h host_name password "new_password"

The account for which this command sets the password is the one with a user table row that matches user_name in the User column and the client host from which you connect in the Host column.

During authentication when a client connects to the server, MySQL treats the password in the user table as an encrypted hash value. When assigning a password to an account, it is important to store an encrypted value, not the cleartext password. Use the following guidelines:

  • When you assign a password using CREATE USER, GRANT with an IDENTIFIED BY clause, or the mysqladmin password command, they encrypt the password for you. Specify the literal cleartext password:

    mysql> CREATE USER 'jeffrey'@'localhost'
        -> IDENTIFIED BY 'mypass';
  • For CREATE USER or GRANT, you can avoid sending the cleartext password if you know the hash value that PASSWORD() would return for the password. Specify the hash value preceded by the keyword PASSWORD:

    mysql> CREATE USER 'jeffrey'@'localhost'
        -> IDENTIFIED BY PASSWORD '*90E462C37378CED12064BB3388827D2BA3A9B689';
  • When you assign an account a nonempty password using SET PASSWORD, you must use the PASSWORD() function to encrypt the password, otherwise the password is stored as cleartext. Suppose that you assign a password like this:

        -> 'jeffrey'@'localhost' = 'mypass';

    The result is that the literal value 'mypass' is stored as the password in the user table, not the encrypted value. When jeffrey attempts to connect to the server using this password, the value is encrypted and compared to the value stored in the user table. However, the stored value is the literal string 'mypass', so the comparison fails and the server rejects the connection with an Access denied error.


PASSWORD() encryption differs from Unix password encryption. See Section 6.3.1, “User Names and Passwords”.

Although it is preferable to modify passwords using SET PASSWORD, GRANT, or mysqladmin, it is also possible to modify the user table directly. In this case, you must also use FLUSH PRIVILEGES to cause the server to reread the grant tables. Otherwise, the change remains unnoticed by the server until you restart it.

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