链接  +   子查询 + sum(if())函数
select
    c.name,
    count(*)
from film f
left join film_category fc
on f.film_id = fc.film_id
left join category c on fc.category_id = c.category_id
where description like '%robot%'
and
    (
        select
            sum(if(category_id = c.category_id,1,0)) sum_c
        from film_category
        having sum_c >=5
    )