Syntax
------

DROP USER [IF EXISTS] user_name [, user_name] ...

Description
-----------

The DROP USER statement removes one or more MariaDB accounts. It removes
privilege rows for the account from all grant tables. To use this statement,
you must have the global CREATE USER privilege or the DELETE privilege for the
mysql database. Each account is named using the same format as for the CREATE
USER statement; for example, 'jeffrey'@'localhost'. If you specify only the
user name part of the account name, a host name part of '%' is used. For
additional information about specifying account names, see CREATE USER.

Note that, if you specify an account that is currently connected, it will not
be deleted until the connection is closed. The connection will not be
automatically closed.

If any of the specified user accounts do not exist, ERROR 1396 (HY000)
results. If an error occurs, DROP USER will still drop the accounts that do
not result in an error. Only one error is produced for all users which have
not been dropped:

ERROR 1396 (HY000): Operation DROP USER failed for 'u1'@'%','u2'@'%'

Failed CREATE or DROP operations, for both users and roles, produce the same
error code.

IF EXISTS
---------

If the IF EXISTS clause is used, MariaDB will return a note instead of an
error if the user does not exist.

Examples
--------

DROP USER bob;

DROP USER foo2@localhost,foo2@'127.%';

IF EXISTS:

DROP USER bob;
ERROR 1396 (HY000): Operation DROP USER failed for 'bob'@'%'

DROP USER IF EXISTS bob;
Query OK, 0 rows affected, 1 warning (0.00 sec)

SHOW WARNINGS;
+-------+------+---------------------------------------------+
| Level | Code | Message                                     |
+-------+------+---------------------------------------------+
| Note  | 1974 | Can't drop user 'bob'@'%'; it doesn't exist |
+-------+------+---------------------------------------------+

URL: https://mariadb.com/kb/en/drop-user/