思路：1.以film表为主表连接各表
2.找到描述信息中包含robot的电影对应的分类名称
3.按名称分组计数
4.找到电影总数量>5的分类，放入之前的筛选中
select
c.name
,count(f1.film_id)
from film f1
left join film_category f2 on f1.film_id = f2.film_id
left join category c on f2.category_id = c.category_id
where f1.description like '%robot%'
and c.name in (
select
c.name
from film f1
left join film_category f2 on f1.film_id = f2.film_id
left join category c on f2.category_id = c.category_id
group by 1
having count(f1.film_id)>=5
)
group by 1