ALTER USER user_specification [, user_specification] ...

user_specification:
    user PASSWORD EXPIRE

The ALTER USER statement modifies MySQL accounts. An error occurs if you try to modify a nonexistent account.

To use ALTER USER, you must have the global CREATE USER privilege or the UPDATE privilege for the mysql system database. When the read_only system variable is enabled, ALTER USER additionally requires the SUPER privilege.

Each account name uses the format described in Section 6.2.4, “Specifying Account Names”. The host name part of the account name, if omitted, defaults to '%'. It is also possible to specify CURRENT_USER or CURRENT_USER() to refer to the account associated with the current session.

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

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

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

A client session operates in restricted mode if the account password has been expired. In restricted mode, operations performed within the session result in an error until the user establishes 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)

This restricted mode of operation permits SET statements, which is useful if the account password has a hashing format that requires old_passwords to be set to a value different from its default before using SET PASSWORD.

It is possible for an administrative user to reset the account password, but any existing sessions for the account remain restricted. A client using the account must disconnect and reconnect before statements can be executed successfully.