convert date to timestamp
in my application i want compare the timestamp values to date field values ,
my database countains many records with their corresponding timestamps values: in this form (" 2017-05-17T13:45:40").
i've also a small database as a patient program wich has a date in this form : 2017-09-25 11:00:00
so , my question is : i want to extract a pairs of (profile_id, timestamp) with the recent timestamps value as condition
after i compare timestamp value to a date values in my second database
i found also that timestamp and date don't have a same form (i want to convert date de timestamps form in green).