ORIGINAL_LOGIN (Transact-SQL)
Returns the name of the login that connected to the instance of SQL Server. You can use this function to return the identity of the original login in sessions in which there are many explicit or implicit context switches.
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Transact-SQL Syntax Conventions
Syntax
ORIGINAL_LOGIN( )
Return Types
sysname
Remarks
This function can be useful in auditing the identity of the original connecting context. Whereas functions such as SESSION_USER and CURRENT_USER return the current executing context, ORIGINAL_LOGIN returns the identity of the login that first connected to the instance of SQL Server in that session.
Examples
The following example switches the execution context of the current session from the caller of the statements to login1. The functions SUSER_SNAME and ORIGINAL_LOGIN are used to return the current session user (the user to whom the context was switched), and the original login account.
USE AdventureWorks2012;
GO
--Create a temporary login and user.
CREATE LOGIN login1 WITH PASSWORD = 'J345#$)thb';
CREATE USER user1 FOR LOGIN login1;
GO
--Execute a context switch to the temporary login account.
DECLARE @original_login sysname;
DECLARE @current_context sysname;
EXECUTE AS LOGIN = 'login1';
SET @original_login = ORIGINAL_LOGIN();
SET @current_context = SUSER_SNAME();
SELECT 'The current executing context is: '+ @current_context;
SELECT 'The original login in this session was: '+ @original_login
GO
-- Return to the original execution context
-- and remove the temporary principal.
REVERT;
GO
DROP LOGIN login1;
DROP USER user1;
GO