Deleting Records

Question

I have a table [user_logs] with the following fields [username], [datetimelog]

Sample Data

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user1   2011-06-28 08:49:01
user2   2011-06-28          


        

Answer 1

DELETE FROM table a WHERE time != (SELECT MAX(time) FROM table b WHERE b.user=a.user);

Here delete a row, if its not the maximum time in group with the same user_id