如何选择包含ID但不包含此列表中的ID的记录

Question

我希望选择包含所选ID的记录，但不包含来自同一列表的这些ID。

我的SQL代码：

select question_id, person_id from `answers` where
`person_id` in ('9', '18')

结果：

2, 9
2, 18
4, 9
4, 18
5, 18
6, 9

预期结果：

5, 18
6, 9

完整SQL查询：

select id, name
from questions
where id not in ('3', '13') and
exists (select `id` from `answers` where `answers`.`question_id` = `questions`.`id`
and `person_id` in ('9', '18')) order by RAND() limit 1

Answer 1

您可以尝试使用分组依据

select question_id, person_id 
from `answers` 
where person_id` in ('9', '18')
group by question_id 
having count(distinct person_id) =  1

仅选择集合中包含person_id的行，但只匹配一个值