SQL - 检查ID是否包含相同的ID值

Question

我想知道如何在不传递（ thread_id ）的情况下检查两个用户（ user_id ）是否在同一个帖子中（ thread_id ）使用SQL，通过下表的结构。

Answer 1

要获得这两个用户所在的所有线程，您可以

select thread_id
from your_table
where user_id in (1,2)
group by thread_id
having count(distinct user_id) = 2

获取具有多个用户的所有线程

select thread_id
from your_table    
group by thread_id
having count(distinct user_id) >= 2

Answer 2

我不太清楚你想要什么，但据我所知，我认为这是。

select thread_id, COUNT(thread_id) AS dup_count  from participant_thread as participant
GROUP BY thread_id
HAVING (COUNT(thread_id) > 1) 

result scrypt

Answer 3

select thread_id, user_id
from thread.thread_table
where thread_id in (
    select thread_id
    from thread.thread_table
    group by thread_id
    having count(user_id) > 1
);