Question

我的SELECT MAX（DATE）代码出现问题;当我运行我的查询时，我按预期获得了3000多行但是我得到[AssigneeID]的重复行而不是只有MAX（DATE）的行？请在运行查询后查看下面的代码和表格示例。

SELECT DISTINCT
i.[RecID] as AssigneeID,
t.[CreatedDateTime]
FROM Incident as i
Left Join Task as t
On i.[RecID] =  t.[ParentLink_RecID] 
WHERE
(t.[CreatedDateTime] IN (SELECT MAX(t.[CreatedDateTime])
             FROM Task as t
             GROUP BY t.[ParentLink_RecID]))
AND i.[Status] <> 'Closed'
AND t.[OwnerTeam] IS NOT NULL
Order By i.[RecID] DESC

AssigneeID                          CreatedDateTime
E94D6F547A73430BA75758C79D5BD8DB    28/05/2013 10:25
E94D6F547A73430BA75758C79D5BD8DB    28/05/2013 10:32
CB208EB6BCC24E1791F946F01D6AF97B    26/03/2013 15:14
CB208EB6BCC24E1791F946F01D6AF97B    16/05/2013 15:20
BE14926E300E45AD8A9A949114CE8026    29/04/2013 10:27
BE14926E300E45AD8A9A949114CE8026    01/05/2013 08:41

提前感谢任何指导

Answer 1

添加GROUP BY语句：

SELECT
i.[RecID] as AssigneeID,
t.[CreatedDateTime]
FROM Incident as i
Left Join Task as t
On i.[RecID] =  t.[ParentLink_RecID] 
WHERE
(t.[CreatedDateTime] IN (SELECT MAX(t.[CreatedDateTime])
             FROM Task as t
             GROUP BY t.[ParentLink_RecID]))
AND i.[Status] <> 'Closed'
AND t.[OwnerTeam] IS NOT NULL
GROUP BY i.[RecID]
Order By i.[RecID] DESC

使用Left Join从另一个表中选择MAX（DATE）？

1 个答案: