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Duplicate records - Select based on latest date

Posted on 2009-04-07
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Last Modified: 2012-05-06
Given the following table:

ID  ItemNo     Datestamp
1   10           2009-03-27 15:58:18.000
2   10           2009-03-27 16:07:14.000
3   20           2009-03-27 16:17:15.000
4   30           2009-03-27 16:42:17.000
5   30           2009-03-27 16:33:33.000
6   40           2009-03-27 16:21:46.000
7   50           2009-03-27 16:49:18.000


Notice that the ID is unique (actually in my table it is a guid) and the ItemNo field has some duplicates.  

I would like to query all the fields in this table and select only the records with the latest datestamp - if there are multiple records with the same item number, get only 1 record for that ItemNo and choose the latest datestamp. How would I do that?

I have tried a few different queries using Group By, but have not been completely successful.


Thanks in advance,


Steve
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Question by:scooper082898
2 Comments
 
LVL 32

Accepted Solution

by:
bhess1 earned 500 total points
ID: 24091971
A query like this should return the data you are looking for....

SELECT m.*
FROM MyTable m
INNER JOIN (
    SELECT ItemNo,
        MAX(DateStamp) as MaxStamp
    FROM MyTable
    GROUP BY ItemNo
    ) Filter
    ON m.ItemNo = Filter.ItemNo
    AND m.DateStamp = MaxStamp
0
 

Author Closing Comment

by:scooper082898
ID: 31567755
Mch appreciated. I have never used "Filter on" before.
0

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