.. _authentication-user_extra_field:

================
User extra field
================

This is mostly useful in case-insensitive username lookups to get the username
returned back using the same casing always. Otherwise depending on your
configuration it may cause problems, such as ``/var/mail/user`` and
``/var/mail/User`` mailboxes created for the same user.

An example ``password_query`` in ``dovecot-sql.conf.ext`` would be:

.. code-block:: none

  password_query = \
    SELECT concat(user, '@', domain) AS user, password \
    FROM users \
    WHERE user = '%n' and domain = '%d'

You can also update "username" and "domain" fields separately:

.. code-block:: none

  password_query = \
    SELECT user AS username, domain, password \
    FROM users \
    WHERE user = '%n' and domain = '%d'