select
name
from
(select
round((min(LATITUDE) + max(LATITUDE)) / 2) as LATITUDE,
round((min(LONGITUDE) + max(LONGITUDE)) / 2) as LONGITUDE
from STATION
where DISTRICT_ID = '110'
AND NAME LIKE 'Vancouver%') AS center
inner join STATION s
where
s.DISTRICT_ID = '110'
and s.NAME like 'Vancouver%'
and s.LATITUDE between center.LATITUDE - 5 and center.LATITUDE + 5
and s.LONGITUDE between center.LONGITUDE - 5 and center.LONGITUDE + 5