On the same table check for 'Status'
Status=9 is Unmanaged
Status=1 is Up
Status=2 is Down
Thanks Vinay. I see now that in the SWQL studio I should have chosen "Generate select statement (with inherited properties)" instead of "Generate select statement". I did the latter, and completely missed the Status field, not to mention the UnManaged field, which seems to give a boolean value for the management status. Looks like that or the Status field you mentioned will do the trick.