For update

[iislas]

Código SQL:

IF (UPDATE (a) OR UPDATE(b))
BEGIN
    INSERT INTO tabla(fecha, a, b)
    SELECT getdate(), a, b
    FROM tablaActualizada ta
    WHERE a EXISTS(SELECT a FROM inserted i WHERE i.a = ta.a ) OR 
    b EXISTS(SELECT b FROM inserted x WHERE x.b = ta.b)
END