как получить значение time из мускула в секундах

[sql]mysql> select second(now());
+---------------+
| second(now()) |
+---------------+
| 44 |
+---------------+
1 row in set (0.00 sec)
[/sql]

[sql]mysql> SELECT TIME_TO_SEC('22:23:00');
+-------------------------+
| TIME_TO_SEC('22:23:00') |
+-------------------------+
| 80580 |
+-------------------------+
1 row in set (0.03 sec)
[/sql]

[sql]mysql> SELECT UNIX_TIMESTAMP();
+------------------+
| UNIX_TIMESTAMP() |
+------------------+
| 1283791775 |
+------------------+
1 row in set (0.00 sec)
[/sql]

[sql]mysql> SELECT UNIX_TIMESTAMP('2010-10-01 23:35:20');
+---------------------------------------+
| UNIX_TIMESTAMP('2010-10-01 23:35:20') |
+---------------------------------------+
| 1285961720 |
+---------------------------------------+
1 row in set (0.00 sec)
[/sql]