subquery aggregation

1select name, revenue from (
2	select facs.name, sum(case 
3				when memid = 0 then slots * facs.guestcost
4				else slots * membercost
5			end) as revenue
6		from cd.bookings bks
7		inner join cd.facilities facs
8			on bks.facid = facs.facid
9		group by facs.name
10	) as agg where revenue < 1000
11order by revenue;