USER_NAME (Transact-SQL)

مقالة
05/16/2013

Returns a database user name from a specified identification number.

Topic link icon Transact-SQL Syntax Conventions

Syntax

USER_NAME ( [ id ] )

Arguments

id
Is the identification number associated with a database user. idis int. The parentheses are required.

Return Types

nvarchar(256)

Remarks

When id is omitted, the current user in the current context is assumed. If the parameter contains the word NULL will return NULL.When USER_NAME is called without specifying an id after an EXECUTE AS statement, USER_NAME returns the name of the impersonated user. If a Windows principal accesses the database by way of membership in a group, USER_NAME returns the name of the Windows principal instead of the group.

Examples

A. Using USER_NAME

The following example returns the user name for user ID 13.

SELECT USER_NAME(13);
GO

B. Using USER_NAME without an ID

The following example finds the name of the current user without specifying an ID.

SELECT USER_NAME();
GO

Here is the result set for a user that is a member of the sysadmin fixed server role.

------------------------------

dbo

(1 row(s) affected)

C. Using USER_NAME in the WHERE clause

The following example finds the row in sysusers in which the name is equal to the result of applying the system function USER_NAME to user identification number 1.

SELECT name FROM sysusers WHERE name = USER_NAME(1);
GO

Here is the result set.

name

------------------------------

dbo

(1 row(s) affected)

D. Calling USER_NAME during impersonation with EXECUTE AS

The following example shows how USER_NAME behaves during impersonation.

SELECT USER_NAME();
GO
EXECUTE AS USER = 'Zelig';
GO
SELECT USER_NAME();
GO
REVERT;
GO
SELECT USER_NAME();
GO

Here is the result set.

DBO

Zelig

DBO

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