hvordan man sletter dublerede rækker fra en tabel i mysql

Fungerer tricket med at pakke det ind i et afledt bord for denne sag? (Baseret på http://www.xaprb.com/blog/2006/06/23/how-to-select-from-an-update-target-in-mysql/ )

DELETE FROM employee WHERE (empid, empssn) NOT IN 
(
SELECT  empid, empssn FROM
(
SELECT MIN(empid) AS empid, empssn FROM employee GROUP BY empssn
) X
);

Rediger Ja, det ser ud til at virke i denne ende.