Is this a imple Query?

[DaPi]

Something like:

Select * from
(select streetName,
 count(houseNumber)                over (partition by streetName) as tot_houses,
 sum(decode(occupiedFlag,'Y',1,0)) over (partition by streetName) as occ_houses)
where occ_houses = tot_houses
where occ_houses < tot_houses and occ_houses <> 0
where occ_houses = 0