MySQL: Как groupby работает с столбцами без агрегатных функций?

Меня несколько смущает то, как работает группа командой в mysql.

Предположим, у меня есть таблица:

mysql> select recordID, IPAddress, date, httpMethod from Log_Analysis_Records_dalhousieShort;                   
+----------+-----------------+---------------------+-------------------------------------------------+
| recordID | IPAddress       | date                | httpMethod                                      |
+----------+-----------------+---------------------+-------------------------------------------------+
|        1 | 64.68.88.22     | 2003-07-09 00:00:21 | GET /news/science/cancer.shtml HTTP/1.0         | 
|        2 | 64.68.88.166    | 2003-07-09 00:00:55 | GET /news/internet/xml.shtml HTTP/1.0           | 
|        3 | 129.173.177.214 | 2003-07-09 00:01:23 | GET / HTTP/1.1                                  | 
|        4 | 129.173.177.214 | 2003-07-09 00:01:23 | GET /include/fcs_style.css HTTP/1.1             | 
|        5 | 129.173.177.214 | 2003-07-09 00:01:23 | GET /include/main_page.css HTTP/1.1             | 
|        6 | 129.173.177.214 | 2003-07-09 00:01:23 | GET /images/bigportaltopbanner.gif HTTP/1.1     | 
|        7 | 129.173.177.214 | 2003-07-09 00:01:23 | GET /images/right_1.jpg HTTP/1.1                | 
|        8 | 64.68.88.165    | 2003-07-09 00:02:43 | GET /studentservices/responsible.shtml HTTP/1.0 | 
|        9 | 64.68.88.165    | 2003-07-09 00:02:44 | GET /news/sports/basketball.shtml HTTP/1.0      | 
|       10 | 64.68.88.34     | 2003-07-09 00:02:46 | GET /news/science/space.shtml HTTP/1.0          | 
|       11 | 129.173.159.98  | 2003-07-09 00:03:46 | GET / HTTP/1.1                                  | 
|       12 | 129.173.159.98  | 2003-07-09 00:03:46 | GET /include/fcs_style.css HTTP/1.1             | 
|       13 | 129.173.159.98  | 2003-07-09 00:03:46 | GET /include/main_page.css HTTP/1.1             | 
|       14 | 129.173.159.98  | 2003-07-09 00:03:48 | GET /images/bigportaltopbanner.gif HTTP/1.1     | 
|       15 | 129.173.159.98  | 2003-07-09 00:03:48 | GET /images/left_1g.jpg HTTP/1.1                | 
|       16 | 129.173.159.98  | 2003-07-09 00:03:48 | GET /images/webcam.gif HTTP/1.1                 | 
+----------+-----------------+---------------------+-------------------------------------------------+

Когда я выполняю этот оператор, как он выбирает, какой идентификатор записи включать, поскольку существует диапазон идентификаторов записи , который был бы правильным? Он просто выбирает первый из подходящих?

mysql> select recordID, IPAddress, date, httpMethod from Log_Analysis_Records_dalhousieShort GROUP BY IPADDRESS;
+----------+-----------------+---------------------+-------------------------------------------------+
| recordID | IPAddress       | date                | httpMethod                                      |
+----------+-----------------+---------------------+-------------------------------------------------+
|       11 | 129.173.159.98  | 2003-07-09 00:03:46 | GET / HTTP/1.1                                  | 
|        3 | 129.173.177.214 | 2003-07-09 00:01:23 | GET / HTTP/1.1                                  | 
|        8 | 64.68.88.165    | 2003-07-09 00:02:43 | GET /studentservices/responsible.shtml HTTP/1.0 | 
|        2 | 64.68.88.166    | 2003-07-09 00:00:55 | GET /news/internet/xml.shtml HTTP/1.0           | 
|        1 | 64.68.88.22     | 2003-07-09 00:00:21 | GET /news/science/cancer.shtml HTTP/1.0         | 
|       10 | 64.68.88.34     | 2003-07-09 00:02:46 | GET /news/science/space.shtml HTTP/1.0          | 
+----------+-----------------+---------------------+-------------------------------------------------+
6 rows in set (0.00 sec)

Для этой таблицы значения max (date) и min (date) кажутся мне логичными, но я не понимаю, как значения recordID и ] httpMethod где выбрано.

Безопасно ли использовать две агрегатные функции в одной команде?

mysql> select recordID, IPAddress, min(date), max(date), httpMethod from Log_Analysis_Records_dalhousieShort GROUP BY IPADDRESS;
+----------+-----------------+---------------------+---------------------+-------------------------------------------------+
| recordID | IPAddress       | min(date)           | max(date)           | httpMethod                                      |
+----------+-----------------+---------------------+---------------------+-------------------------------------------------+
|       11 | 129.173.159.98  | 2003-07-09 00:03:46 | 2003-07-09 00:03:48 | GET / HTTP/1.1                                  | 
|        3 | 129.173.177.214 | 2003-07-09 00:01:23 | 2003-07-09 00:01:23 | GET / HTTP/1.1                                  | 
|        8 | 64.68.88.165    | 2003-07-09 00:02:43 | 2003-07-09 00:02:44 | GET /studentservices/responsible.shtml HTTP/1.0 | 
|        2 | 64.68.88.166    | 2003-07-09 00:00:55 | 2003-07-09 00:00:55 | GET /news/internet/xml.shtml HTTP/1.0           | 
|        1 | 64.68.88.22     | 2003-07-09 00:00:21 | 2003-07-09 00:00:21 | GET /news/science/cancer.shtml HTTP/1.0         | 
|       10 | 64.68.88.34     | 2003-07-09 00:02:46 | 2003-07-09 00:02:46 | GET /news/science/space.shtml HTTP/1.0          | 
+----------+-----------------+---------------------+---------------------+-------------------------------------------------+
6 rows in set (0.00 sec)