When dealing with dates and MySQL often you have to work data that's in unixtime. If you want to insert data into a MySQL table with a datetime field you can do this:

INSERT INTO MyTable VALUES (MyDateField) (FROM_UNIXTIME(1285695703));

If you have data in MySQL as a datetime and you want to extract it as unixtime do this:

SELECT UNIX_TIMESTAMP(MyDateField) AS MyUnixField FROM MyTable;