php dates and postgres

Hello, I need to query my db to find out if an entry has been updated since a date the user enters (mm/dd/yyyy). Can I do something like the stuff below? Or do I need to do the extract epoch stuff backwards somehow? $timestamp = strtotime($user_date); $postgres_format = date(format info that matches the postgres format, $timestamp); and then use $postgres_format to see if something is newer/older when I do my SQL? When I enter things can I use something similar (if I can't use now())? Thanks! Natalie