下面语句可以找到什么书卖得最多,按降序排列 select k.name,count(1)as b_count from t_buy b
join t_book k on b.bookid=k.id
join t_person p on b.personid=p.id
and p.age between 20 and 30
group by b.bookid order by b_count desc
select bookId , (select name from t_book where id=bookId) from ( select bookId,count(*) as c from t_person p inner join t_buy b on p.id=b.personId where p.age between 20 and 30 ) a where c=(select max(c) as macx from ( select bookId,count(*) as c from t_person p inner join t_buy b on p.id=b.personId where p.age between 20 and 30 )b )
join t_book k on b.bookid=k.id
join t_person p on b.personid=p.id
and p.age between 20 and 30
group by b.bookid order by b_count desc
from (
select bookId,count(*) as c
from t_person p inner join t_buy b on p.id=b.personId
where p.age between 20 and 30
) a
where c=(select max(c) as macx
from (
select bookId,count(*) as c
from t_person p inner join t_buy b on p.id=b.personId
where p.age between 20 and 30
)b
)