拉特定記錄只匹配多個行中的一組值

Question

我正在嘗試查找所有僅包含一組確切收件人的對話。我的表是這樣的：

Conversation 
--------------- 
id | some other fields 

User 
--------------- 
id | some other fields 

Recipients 
-------------- 
id | conversation_id | user_id | some other fields 
1 | 1    | 1 
2 | 1    | 2   
3 | 2    | 1 
4 | 2    | 2     
5 | 2    | 3 
6 | 3    | 1 
7 | 3    | 3 

使用上面我想conversation_id 1，我唯一知道的是USER_ID的[1,2]，但我不希望任何其他記錄我將如何去這樣做。

Answer 1

您可以對conversation_id進行分組，然後使用having過濾出正確的對話。在下面的查詢中，第一行要求存在user_id 1和2。第二行要求，它不包含任何其他user_id：

select conversation_id 
from recipients 
group by 
     conversation_id 
having count(distinct case when user_id in (1,2) then user_id end) = 2 
     and count(case when user_id not in (1,2) then 1 end) = 0 

Answer 2

如果我正確理解：

SELECT id 
, conversation_id 
, user_id 
, ... other columsn 
FROM Recipients 
WHERE converstaion_id = 1 
AND user_id IN (1,2) 

Answer 3

select c.* from Conversation c 
    where (select count(distinct user_id) from Recipients 
    where conversation_id=c.id and user_id in (<USER-IDS>))=<NUMBER-OF-USERS> 

其中< USER-IDS>是逗號分隔的用戶ID和< NUMBER-OF-USERS>是那些用戶的確切數目，例如2在你的例子中。

Answer 4

先找到至極conversation_id有無USER_ID不在列表（內部子查詢）然後找到conversation_id不在這個名單

SELECT DISTINCT conversation_id 
FROM   dbo.Recipients 
WHERE  (conversation_id NOT IN 
          (SELECT  Recipients_1.conversation_id 
          FROM   dbo.Recipients AS Recipients_1 LEFT OUTER JOIN 
                 (SELECT id AS user_id 
                 FROM   User 
                 WHERE  (id IN (1, 2))) AS tbl_user ON tbl_user.user_id = Recipients_1.user_id 
          WHERE  (tbl_user.user_id IS NULL)))