ALTER USER user_specification
    [, user_specification] ...

user_specification:
    user PASSWORD EXPIRE

The ALTER USER statement alters MySQL accounts. To use it, you must have the global CREATE USER privilege or the INSERT privilege for the mysql database.

For each account, ALTER USER expires its password. For example:

ALTER USER 'jeffrey'@'localhost' PASSWORD EXPIRE;

The account name uses the format described in Section 6.2.3, “Specifying Account Names”. If you specify only the user name part of the account name, a host name part of '%' is used.

Password expiration for an account affects the corresponding row of the mysql.user table: The server sets the password_expired column to 'Y'.

After an account's password has been expired, all operations performed in subsequent connections to the server using the account result in an error until the user issues a SET PASSWORD statement to establish a new account password:

mysql> SELECT 1;
ERROR 1820 (HY000): You must SET PASSWORD before executing this statement

mysql> SET PASSWORD = PASSWORD('new_password');
Query OK, 0 rows affected (0.01 sec)

mysql> SELECT 1;
+---+
| 1 |
+---+
| 1 |
+---+
1 row in set (0.00 sec)

As of MySQL 5.6.8, this restricted mode of operation also permits SET statements, which is useful if the account password uses a hashing format that requires old_passwords to be set to a value different from its default.

It is also possible for an administrative user to reset the account password, but any existing connections for the account remain under restriction. Clients using the account must disconnect and reconnect before statements can be executed successfully.

It is possible after password expiration to “reset” a password by using SET PASSWORD to set it to its current value. As a matter of good policy, it is preferable to choose a different password.