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

Answer 2

DELETE from user_logs UL1, user_logs UL2
where UL1.username =UL2.datetimelog
and UL1.datetimelog < UL2.datetimelog

Try that

Answer 3

What about:

DELETE FROM 
    MY_TABLE M -- delete from the table
LEFT JOIN
    MY_TABLE M2 ON M.user = M2.user -- table needs to be joined TO ITSELF
WHERE
    NOT M.LOG_DATE = MAX( M2.LOG_DATE ) -- Anything which isn't MAX goes.

Could that work?