MySQL 9.3 Reference Manual Including MySQL NDB Cluster 9.3
The USER_ATTRIBUTES
table provides
information about user comments and user attributes. It takes its
values from the mysql.user
system table.
The USER_ATTRIBUTES
table has these
columns:
USER
The user name portion of the account to which the
ATTRIBUTE
column value applies.
HOST
The host name portion of the account to which the
ATTRIBUTE
column value applies.
ATTRIBUTE
The user comment, user attribute, or both belonging to the
account specified by the USER
and
HOST
columns. The value is in JSON object
notation. Attributes are shown exactly as set using
CREATE
USER
and
ALTER
USER
statements with ATTRIBUTE
or
COMMENT
options. A comment is shown as a
key-value pair having comment
as the key.
For additional information and examples, see
CREATE USER Comment and Attribute Options.
USER_ATTRIBUTES
is a nonstandard
INFORMATION_SCHEMA
table.
To obtain only the user comment for a given user as an unquoted string, you can employ a query such as this one:
mysql>SELECT ATTRIBUTE->>"$.comment" AS Comment
->FROM INFORMATION_SCHEMA.USER_ATTRIBUTES
->WHERE USER='bill' AND HOST='localhost';
+-----------+ | Comment | +-----------+ | A comment | +-----------+
Similarly, you can obtain the unquoted value for a given user attribute using its key.
USER_ATTRIBUTES
contents are
accessible as follows:
All rows are accessible if:
The current thread is a replica thread.
The access control system has not been initialized
(for example, the server was started with the
--skip-grant-tables
option).
The currently authenticated account has the
UPDATE
or
SELECT
privilege for
the mysql.user
system table.
The currently authenticated account has the
CREATE USER
and
SYSTEM_USER
privileges.
Otherwise, the currently authenticated account can see the
row for that account. Additionally, if the account has the
CREATE USER
privilege but
not the SYSTEM_USER
privilege, it can see rows for all other accounts that do
not have the SYSTEM_USER
privilege.
For more information about specifying account comments and attributes, see Section 15.7.1.3, “CREATE USER Statement”.