I have a table and I'm trying to remove all the duplicate and keep the
the rows that has the latest datestamp.

Here is the table:

email address       orgin_date   new_opt_in_date   datestamp
123@ax.tu            1/1/1900     1/1/1900          3/15/2016
123@ax.tu            1/1/1900     1/1/1900          3/15/2016
iron_man@metrix.com  2/15/2015    3/5/2015          6/6/2017
iron_man@metrix.com  2/15/2015    3/5/2015          7/6/2018
sleep@dort.st        2/15/2015    3/5/201           7/6/2018
sleep@dort.st        2/15/2015    3/5/201           5/6/2018

I'm trying to keep only the data that has the recent datestamp, delete the
rest and hope that the
output will like this:
email address       orgin_date   new_opt_in_date   datestamp
123@ax.tu            1/1/1900     1/1/1900          3/15/2016
iron_man@metrix.com  2/15/2015    3/5/2015          6/6/2017
sleep@dort.st        2/15/2015    3/5/201           7/6/2018

DELETE FROM `tablename`
WHERE datestamp
NOT IN (
SELECT * FROM (
  SELECT MAX(datestamp) FROM tablename
    GROUP BY emailaddress
 )
 )
but nothing it didn't work