1 1 典型SQL语句试题整理

Discuss(user1, user2, topic) (1)SQL:所有被Alice和Bob讨论但不被Alice和Crowe讨论的话题 select topic from Discuss where user1=’Alice’ and user2=’Bob’ EXCEPT select topic from Discuss where user1=’Alice’ and user2=’Crowe’ intersect(交) (2)SQL:被超过10对用户讨论的话题的个数 select count(*) from ( select topic from Discuss group by to