如何为此SQL查询编写左外连接？

Question

我有一个表像

ParsereplyId Message Callid status EMailid  subject 

------------------------------------------------------------------------ 
     1  hi   2222 Replied g.m.p@m.com Log a cll 
     2  hello  2222 Replied g.m.p@m.com Re: 
     3  hi2  2222 New  g.m.p@m.com Re:log a cll 
     4  hello2  2223 Read  g.p@m.com  Log a cldf 
     5  how r u 2223 New  g.p@m.com  Re:Log a 

从上面的表格我想下面的输出：

ParsereplyId Message Callid status EMailid  subject 

------------------------------------------------------------------- 
     3  hi2  2222 New  g.m.p@m.com Re:log a cll 
     5  how r u 2223 New  g.p@m.com  Re:Log a 

我曾尝试下面的查询。 但我想做到在LEFT OUTER JOIN

SELECT A.[ParsedReplyId] 
       , A.[EMailId] 
       , A.[Message] 
       , A.[CallId] 
       , [UM_User].[UserName]     
FROM IM_IncidentReplyMail AS A 
     INNER JOIN 
       (SELECT MAX(ParsedReplyId) AS parseid 
       FROM [IM_IncidentReplyMail] 
       GROUP BY [CallId]) AS B 
     INNER JOIN 
     [UM_User] ON [UM_User].[EmailId] = A.[EmailId] 
     WHERE 
      B.parseid = A.[ParsedReplyId] 

如何实现上面的SQL查询内部联接？

编辑：我纠正了我的错误上面

UM_USer表包含​​3210，基于电子邮件ID从两个表中我能得到该邮件的用户名。

编辑2： 我可以使用左外连接，而不是使用内部联接像

SELECT A.[ParsedReplyId] 
        , A.[EMailId] 
        , A.[Message] 
        , A.[CallId] 
        , [UM_User].[UserName]     
      FROM IM_IncidentReplyMail AS A 
      LEFT OUTER JOIN 
        (SELECT MAX(ParsedReplyId) AS parseid 
        FROM [IM_IncidentReplyMail] 
        GROUP BY [CallId]) AS B 
      ON 1=1 
      LEFT OUTER JOIN 
      [UM_User] ON [UM_User].[EmailId] = A.[EmailId] 
      WHERE 
       B.parseid = A.[ParsedReplyId] 

在这里，我使用1 = 1个条件这是不是在查询中使用的正确方式。它使我的代码变得丑陋。所以我要求你帮忙解决这个问题。

Answer 1

我已经按照你需要的输出

DECLARE @Table1 TABLE 
     (Id INT, Message VARCHAR(7), Call INT, status VARCHAR(7), EMail VARCHAR(11), subject VARCHAR(12)) 
    ; 

    INSERT INTO @Table1 
     (Id, Message, Call, status, EMail, subject) 
    VALUES 
     (1, 'hi', 2222, 'Replied', 'g.m.p@m.com', 'Log a cll'), 
     (2, 'hello', 2222, 'Replied', 'g.m.p@m.com', 'Re:'), 
     (3, 'hi2', 2222, 'New', 'g.m.p@m.com', 'Re:log a cll'), 
     (4, 'hello2', 2223, 'Read', 'g.p@m.com', 'Log a cldf'), 
     (5, 'how r u', 2223, 'New', 'g.p@m.com', 'Re:Log a') 
    ; 

     SELECT T.Id, 
     TT.Message, 
     TT.Call, 
     TT.status, 
     TT.EMail, 
     TT.subject 
     FROM @Table1 tt 
     LEFT OUTER JOIN 
     (
     SELECT Id, 
     MAX(subject) OVER(PARTITION BY call ORDER BY call) subject, 
     MAX(Message) OVER(PARTITION BY call ORDER BY call) Message FROM @Table1)T 
     ON T.Id = TT.Id AND T.Message = TT.Message AND T.subject = TT.subject 
WHERE T.id IS NOT NULL