MySQL: select 具有特定字段值的多行

Question

我有一个 users_conversations 表，其中包含一个 conversation_id 和一个 user_id 来告诉哪些用户在同一个对话中。 我想找到任何具有 user_id 76 和 user_id 146 的对话 ID（它们是 id 28、31 和 32。这些 id 对我来说并不陌生。我只有两个用户 id）我试过

select * from users_conversations where user_id = 146 or user_id = 76 GROUP BY conversation_id

但我明白了

#1055 - Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 
'forums.users_conversations.user_id' which is not functionally dependent on columns in GROUP BY clause; 
this is incompatible with sql_mode=only_full_group_by

我怎样才能做到这一点？

Answer 1

select * from users_conversations
where conversations_id in (select conversations_id from user_conversations where user_id=76) 
AND conversations_id in (select conversations_id from user_conversations where user_id=146)

Answer 2

您可以过滤这些用户的表， group by conversation_id并在having子句中设置条件：

select conversation_id
from users_conversations
where user_id in (76, 146)
group by conversation_id
having count(distinct user_id) = 2

如果每个conversation_id没有重复用户的情况，您可以省略distinct 。

Answer 3

你的意思是不是：

select * from users_conversations where user_id = 146 or user_id = 76

为什么要使用组？