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Sql query to last records from table

Posted on 2016-10-05
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Last Modified: 2016-10-08
I have sql table with these columns
CrewID
Lat
Lon
DateCreated

Now this table stores Latitude and Longitude of each crew when he travels along with Datetime when the position is recorded.

I need to write a query which will give me the last recorded position of each crew from this table bases on DateCreated.
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Question by:yadavdep
3 Comments
 
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Accepted Solution

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Jim Horn earned 500 total points
ID: 41830134
<Knee jerk reaction.  Write a subquery to get the most recent DateCreated for each CrewID, then join on the table as a main query.  Change YourTable and aliases to meet your needs. > 

SELECT yt.CrewID, yt.Lat, yt.Lon, yt.DateCreated
FROM YourTable yt
   JOIN (
      SELECT CrewID, Max(DateCreated) as DateCreatedMax
      FROM YourTable
      GROUP BY CrewID) ytmax ON yt.CrewID = ytmax.CrewID AND yt.DateCreated = ytmax.DateCreatedMax
ORDER BY yt.CrewID

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Expert Comment

by:Scott Pletcher
ID: 41830605
SELECT CrewID, Lat, Lon, DateCreated
FROM (
    SELECT *, ROW_NUMBER() OVER(PARTITION BY CrewID ORDER BY DateCreated DESC) AS row_num
    FROM table_name
) AS derived
WHERE row_num = 1
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Expert Comment

by:Pawan Kumar
ID: 41830978
SELECT x.CrewID, x.Lat, x.Lon, n.DateCreated
FROM YourTable x
CROSS APPLY
(
        SELECT MAX(y.DateCreated) DateCreated
	FROM YourTable y
	WHERE x.CrewID = y.CrewID    
)n

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