select * 
from order_info
where user_id in 
(
    select user_id 
    from order_info a
    where date>'2025-10-15'
    and product_name in ('C++','Java','Python')
    and status='completed'
    group by user_id 
    having count(user_id)>=2
)
and product_name in ('C++','Java','Python')
and status='completed'
and date>'2025-10-15'
order by id

思路：和（二）一样，不过不能使用group by 了，不过我们可以先用group by 把符合条件的user_id 求出来，然后再用判断条件就得到正确答案了。