Need Assistance With A Select Query.

I am new to SQL and aftering reading my SQL For Dummies book, I still am unsure how to accomplish this task.

The table I need to query contains resident census information. There are multiple rows for each resident. I need to determine if the resident is still active, so I only need to read the last row for each resident to make this determination.

What method can I use to read only the last row for the resident. Here is what I tried previously, but it returns multiple rows for each resident.

select a.firm_id_code as FacAddOnNum,
f.shortname as FacName,
left(a.resident_code,6) as ResidentCode,
(r.res_first_name + ' ' + r.res_last_name) as ResidentName,
a.LastDate,
a.cens_trans_type

from (select firm_id_code,
resident_code,
max(dt_cens_trans) as LastDate,
cens_trans_type
from arrescensus
where firm_id_code = @FacId
group by firm_id_code, resident_code, dt_cens_trans, cens_trans_type) as a
join corp_info.dbo.facilityinfo as f on (a.firm_id_code = f.addonnum)
join arresidents as r on ((r.firm_id_code = a.firm_id_code) and (r.resident_code = a.resident_code))


Any help with this is greatly appreciated!