Drupal stores time information (such as created date, modified date, etc) in unix date format as int(11).
Using a simple statement:
SELECT n.`created` FROM node n
Formats the data as date & time:
SELECT FROM_UNIXTIME(n.created) FROM node n
Just the date:
SELECT DATE(FROM_UNIXTIME(n.created)) FROM node n
Of course, you could (should?) process the date in the software you are using instead.