why do we use in date function php code example

Example 1: date in php

/**
 * Its always best to use a datetime object
 */
$dateTime = new \DateTime();
/**
 * You can get the string by using format
 */
$dateTime->format('Y-m-d H:i:s');

Example 2: show date php

check here link:   http://www.eltcalendar.com/stuff/datemysqlphp.html