10万件のデータでmin()関数を使ったときに実行されない

select A.property_id, A.room_id, A.house_rent from 
     ( select property_id, room_id, house_rent
	from room_cost, room
	where room.id=room_id and house_rent >= 50000 ) A
     inner join 
     ( select property_id, min(house_rent) minprice
           from (select property_id, room_id, house_rent
			from room_cost, room
			where room.id=room_id and house_rent >= 50000) C
           where c.room_id=room_id  group by property_id) B
     on A.property_id = B.property_id and A.house_rent = B.minprice
     group by A.property_id;

select A.property_id, A.room_id, A.house_rent from 
     ( select property_id, room_id, house_rent
           from room_cost ,room
           where room.id =room_id ) A
     inner join 
     ( select property_id, min(house_rent) minprice
           from room_cost ,room
           where room.id=room_id and house_rent >= 50000
           group by property_id) B
     on A.property_id = B.property_id and A.house_rent = B.minprice

C: <example>
select * from room where room.floor >= 10 outer join station where room.id = station.room_id and station.timetaken <= 10
 - 十階以上に存在する部屋で駅が徒歩10分いないの部屋テーブル（本当はstationはMany to Manyだけど面倒いのでOne to Manyと仮定して）
C: <example2>
select * from room where room.arrangement == 2DK outer join branch where room.id = branch.room_id and branch.name in ('東京支店', '京都支店')
 - 間取りが2DKで取扱い支店が'東京支店'か'京都支店'のテーブル

select A.property_id, A.room_id, A.house_rent from 
     ( select property_id, room_id, house_rent
           from room_cost ,room
           where room.id =room_id ) A
     inner join 
     ( select property_id, min(house_rent) minprice
           from C
           where room.id=room_id
           group by property_id) B
     on A.property_id = B.property_id and A.house_rent = B.minprice