How to obtain the authentication name of the current user using the CURRENT_USER() function?

CURRENT_USER() is a MySQL built-in function that returns the authentication name of the current user. The authentication name is a combination of "User" and "Host" columns in the mysql.user table and used to authenticate you into the system. For example:

SELECT CURRENT_USER();
  -- +----------------+
  -- | CURRENT_USER() |
  -- +----------------+
  -- | fyi@%          |
  -- +----------------+

SELECT User, Host, authentication_string FROM mysql.user WHERE User = 'fyi';
  -- +------+-----------+-------------------------------------------+
  -- | User | Host      | authentication_string                     |
  -- +------+-----------+-------------------------------------------+
  -- | fyi  | %         | *94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29 |
  -- | fyi  | localhost | *3735F1D8464342BA852E10101E55E422EBAAAF35 |
  -- +------+-----------+-------------------------------------------+

Note that the related USER() function returns the login name of user, which is the combination of user name and the client IP where you logged in from. So the login name returned from USER() may differ from the authentication name returned by CURRENT_USER(). For example:

SELECT USER(), CURRENT_USER();
  -- +------------------+----------------+
  -- | USER()           | CURRENT_USER() |
  -- +------------------+----------------+
  -- | fyi@192.168.1.11 | fyi@%          |
  -- +------------------+----------------+

Reference information of the CURRENT_USER() function:

CURRENT_USER(): user
  Returns the authentication name of the current user.

Arguments, return value and availability:
  user: Return value. The authentication name of the current user.
  Available since MySQL 4.0.

Related MySQL functions:

• USER() - Login Name of Current User
• SESSION_USER() - Synonym for USER()
• SYSTEM_USER() - Synonym for USER()
• CURRENT_USER() - Authentication Name of Current User

⇒ DATABASE() - Name of Current Database

⇐ CURRENT_ROLE() - Current Role of Logged-In User

⇑ MySQL Functions on System Information

⇑⇑ MySQL Function References