根据时间戳删除重复记录

Question

我正在编写查询以查找重复记录。我有以下列的表格

Id, Deliveries, TankId, Timestamp.

我已经插入了重复记录，即同一坦克， 1天的偏移时间戳。

。

现在，我想删除带有较小时间戳的重复记录。

例如。我在7月24日和25日为同一坦克增加了重复的交付。我需要删除第24个记录。

我尝试了以下查询;

SELECT raw.TimeStamp,raw.[Delivery],raw.[TankId]
FROM  [dbo].[tObservationData] raw
INNER JOIN (
    SELECT [Delivery],[TankSystemId]
    FROM [dbo].[ObservationData] 
    GROUP BY [Delivery],[TankSystemId]
    HAVING COUNT([ObservationDataId]) > 1
    ) dup 
    ON raw.[Delivery] = dup.[Delivery] AND raw.[TankId] = dup.[TankId]
    AND  raw.TimeStamp >'2019-06-30 00:00:00.0000000' AND raw.[DeliveryL]>0
ORDER BY [TankSystemId],TimeStamp

，但上面也提供了其他记录，我如何找到并删除这些重复记录？

Answer 1

您只是在寻找这个吗？

SELECT od.*
FROM (SELECT od.*,
             ROW_NUMBER() OVER (PARTITION BY od.TankId, od.Delivery ORDER BY od.TimeStamp DESC) as seqnum
      FROM [dbo].[tObservationData] od
     ) od
WHERE seqnum = 1;

Answer 2

在这种情况下，您可以按子句按顺序使用分区。您可以按TANKID，交货和订单按时间戳记按DESC顺序进行分区

Select * from (
Select *,ROW_NUMBER() OVER (PARTITION BY TankID,Delievry ORDER BY [Timestamp] DESC) AS rn
from [dbo].[ObservationData]
) 
where rn = 1

在上述代码记录中，rn = 1将具有最新的时间戳。因此，您只能选择这些并忽略其他人。另外，您可以使用相同的内容来删除/删除表中的记录。

WITH TempObservationdata (TankID,Delivery,Timestamp)
AS
(
SELECT TankID,Delivery,ROW_NUMBER() OVER(PARTITION by TankID, Delivery ORDER BY Timsetamp desc) 
AS Timestamp
FROM dbo.ObservationData
)
--Now Delete Duplicate Rows
DELETE FROM TempObservationdata 
WHERE Timestamp > 1

Answer 3

认为它将起作用

SELECT raw.TimeStamp,raw.[Delivery],raw.[TankId]
FROM  [dbo].[tObservationData] raw
INNER JOIN (
    SELECT [Delivery],[TankSystemId],min([TimeStamp]) as min_ts
    FROM [dbo].[ObservationData] 
    GROUP BY [Delivery],[TankSystemId]
    HAVING COUNT([ObservationDataId]) > 1
    ) dup 
    ON raw.[Delivery] = dup.[Delivery] AND raw.[TankId] = dup.[TankId] and raw.[TimeStamp] = dup.min_ts
    AND  raw.TimeStamp >'2019-06-30 00:00:00.0000000' AND raw.[DeliveryL]>0
ORDER BY [TankSystemId],TimeStamp