Question

我有一个看起来像这样的临时表：

RequestID   | CreatedDate          | HistoryStatus           
CF-0000001  | 8/26/2009 1:07:01 PM | For Review   
CF-0000001  | 8/26/2009 1:07:01 PM | Completed  
CF-0000112  | 8/26/2009 1:07:01 PM | For Review   
CF-0000113  | 8/26/2009 1:07:01 PM | For Review  
CF-0000114  | 8/26/2009 1:07:01 PM | Completed  
CF-0000115  | 8/26/2009 1:07:01 PM | Completed

我希望桌子看到最后的结果是这样的：

RequestID   | CreatedDate          | HistoryStatus           
CF-0000001  | 8/26/2009 1:07:01 PM | Completed  
CF-0000112  | 8/26/2009 1:07:01 PM | For Review  
CF-0000113  | 8/26/2009 1:07:01 PM | For Review  
CF-0000114  | 8/26/2009 1:07:01 PM | Completed  
CF-0000115  | 8/26/2009 1:07:01 PM | Completed

即。应删除重复的CF-0000001。

如果有多个重复行且仍然返回不重复的行，我该如何返回或者我应该只选择一行？

Answer 1

如果要根据RequestID和CreatedDate显示重复行之一并显示最新的HistoryStatus，请尝试此操作。

with t as (select row_number()over(partition by RequestID,CreatedDate order by RequestID) as rnum,* from tbltmp)
Select RequestID,CreatedDate,HistoryStatus from t a where  rnum in (SELECT Max(rnum) FROM t GROUP BY RequestID,CreatedDate having t.RequestID=a.RequestID)

或者如果您只想选择CreatedDate中的一个重复行并显示最新的HistoryStatus，请尝试以下查询。

with t as (select row_number()over(partition by CreatedDate order by RequestID) as rnum,* from tbltmp)
Select RequestID,CreatedDate,HistoryStatus from t  where  rnum = (SELECT Max(rnum) FROM t)

或者，如果您想选择仅考虑请求ID的重复行之一并显示最新的HistoryStatus，请使用下面的查询

with t as (select row_number()over(partition by RequestID order by RequestID) as rnum,* from tbltmp)
Select RequestID,CreatedDate,HistoryStatus from t a where  rnum in (SELECT Max(rnum) FROM t GROUP BY RequestID,CreatedDate having t.RequestID=a.RequestID)

我在sql server 2005中编写的所有上述查询。

Answer 2

从标题我猜你每个独特的行只需要一个结果？如果是这种情况，请查看GROUP BY子句（或SELECT DISTINCT）。

Answer 3

select t.*
from (
    select RequestID, max(CreatedDate) as MaxCreatedDate
    from table1
    group by RequestID
) tm
inner join table1 t on tm.RequestID = t.RequestID and tm.MaxCreatedDate = t.CreatedDate

Answer 4

如果查询中存在一对多关系，则可能会在一侧出现重复的行。

假设以下

TABLE TEAM
ID       TEAM_NAME
0        BULLS
1        LAKERS


TABLE PLAYER
ID       TEAM_ID     PLAYER_NAME
0        0           JORDAN
1        0           PIPPEN

然后执行类似

的查询

SELECT 
    TEAM.TEAM_NAME, 
    PLAYER.PLAYER_NAME 
FROM TEAM
INNER JOIN PLAYER

你会得到

TEAM_NAME   PLAYER_NAME
BULLS       JORDAN
BULLS       PIPPEN

所以你将拥有重复的TEAM NAME。即使使用DISTINCT子句，您的结果集也将包含重复的TEAM NAME

因此，如果您不想在查询中使用重复的TEAM_NAME，请执行以下操作

SELECT ID, TEAM_NAME FROM TEAM

对于遇到的每个团队ID执行

SELECT PLAYER_NAME FROM PLAYER WHERE TEAM_ID = <PUT_TEAM_ID_RIGHT_HERE>

所以这样你就不会在一边获得重复参考

的问候，

Answer 5

如果这是一个SQL问题，并且我理解你在问什么，（它并不完全清楚），只需在查询中添加distinct

   Select Distinct * From TempTable

Answer 6

select * from temptable
where rnum --unique key
 in 

( 
 SELECT RNUM --unique key
  FROM temptable
 WHERE (  HistoryStatus
) IN (SELECT                HistoryStatus

                             FROM temptable
                            GROUP BY                
HistoryStatus 
                           HAVING COUNT(*) <= 1));

我还没有测试过这段代码。我使用了类似的代码，它的工作原理。语法在Oracle中。

Answer 7

使用命名空间和子查询您可以这样做：

declare @data table (RequestID varchar(20), CreatedDate datetime, HistoryStatus varchar(20))
insert into @data values ('CF-0000001','8/26/2009 1:07:01 PM','For Review');
insert into @data values ('CF-0000001','8/26/2009 1:07:01 PM','Completed');  
insert into @data values ('CF-0000112','8/26/2009 1:07:01 PM','For Review');   
insert into @data values ('CF-0000113','8/26/2009 1:07:01 PM','For Review');  
insert into @data values ('CF-0000114','8/26/2009 1:07:01 PM','Completed');  
insert into @data values ('CF-0000115','8/26/2009 1:07:01 PM','Completed');

select d1.RequestID,d1.CreatedDate,d1.HistoryStatus 
from @data d1 
where d1.HistoryStatus = 'Completed'
union all 
select d2.RequestID,d2.CreatedDate,d2.HistoryStatus 
from @data d2 
where d2.HistoryStatus = 'For Review' 
    and d2.RequestID not in (
        select RequestID 
        from @data 
        where HistoryStatus = 'Completed' 
            and CreatedDate = d2.CreatedDate
    )

以上查询返回

CF-0000001, 2009-08-26 13:07:01.000,    Completed
CF-0000114, 2009-08-26 13:07:01.000,    Completed
CF-0000115, 2009-08-26 13:07:01.000,    Completed
CF-0000112, 2009-08-26 13:07:01.000,    For Review
CF-0000113, 2009-08-26 13:07:01.000,    For Review

Answer 8

尝试使用select distinct x。* from （ 您的查询 ）

感谢。

Answer 9

要从两行的重复列中仅获取一个不同的记录，您可以使用由oracle自身维护的“rowid”列作为主键，因此首先尝试

"select rowid,RequestID,CreatedDate,HistoryStatus  from temptable;"

然后你可以通过在SELECT语句中使用它的'rowid'列的值来获取第二行。

如果多个重复的行仍然返回不重复的行，如何只返回1行？

9 个答案: