public function getDate()
    {
        global $wpdb;
        return $wpdb->get_var($wpdb->prepare('SELECT post_date FROM ' . $wpdb->prefix . 'posts WHERE ID = %d',
            $this->ID));
    }
public function getDate()
    {
        global $wpdb;
        return $wpdb->get_var($wpdb->prepare('SELECT post_date FROM ' . $wpdb->prefix . 'posts WHERE ID = %d',
            $this->ID));
    }
public function getDate ( ) { global $ wpdb ; return $ wpdb -> get_var ( $ wpdb -> prepare ( 'SELECT post_date FROM ' . $ wpdb -> prefix . 'posts WHERE ID = %d' , $ this -> ID ) ) ; }
Return the publish date

@return string
Return the publish date