sp_change_users_login

--Create the new login.  
CREATE LOGIN MaryB WITH PASSWORD = '982734snfdHHkjj3';  
GO  
--Map database user MB-Sales to login MaryB.  
USE AdventureWorks2012;  
GO  
EXEC sp_change_users_login 'Update_One', 'MB-Sales', 'MaryB';  
GO

sp_change_users_login(Transact-SQL) – SQL 서버 | 마이크로소프트 런