SQL T-SQL Merge Command

This is a sample that we can use it:

-- MERGE statement with the join conditions specified correctly.
USE tempdb;
GO
BEGIN TRAN;
MERGE Target AS T
USING Source AS S
ON (T.EmployeeID = S.EmployeeID)
WHEN NOT MATCHED BY TARGET AND S.EmployeeName LIKE 'S%'
    THEN INSERT(EmployeeID, EmployeeName) VALUES(S.EmployeeID, S.EmployeeName)
WHEN MATCHED
    THEN UPDATE SET T.EmployeeName = S.EmployeeName
WHEN NOT MATCHED BY SOURCE AND T.EmployeeName LIKE 'S%'
    THEN DELETE
OUTPUT $action, inserted.*, deleted.*;
ROLLBACK TRAN;
GO


For further information:
https://technet.microsoft.com/pt-BR/library/bb522522(v=sql.105).aspx