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.
To view Transact-SQL syntax for SQL Server 2014 and earlier, see Previous versions documentation.
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.
The following example switches the execution context of the current session from the caller of the statements to
login1. The functions
ORIGINAL_LOGIN are used to return the current session user (the user to whom the context was switched), and the original login account.
Although the ORIGINAL_LOGIN function is supported on Azure SQL Database, the following script will fail because Execute as LOGIN is not supported on Azure SQL Database.
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