consulta SQL, dificil(?)

[quimfv]

Código:

SELECT Sub.TIEMPO, Sub.MEDIDA1, Sub.MEDIDA2
FROM (SELECT TIEMPO, MEDIDA1, NULL as MEDIDA2
           FROM TABLA1
           UNION ALL
           SELECT TIEMPO, NULL as MEDIDA1, MEDIDA2
           FROM TABLA2) as Sub
ORDER BY Sub.TIEMPO;

Si?

Quim