MySQL Tutorial/Date Time Functions/TIME TO SEC

SELECT TIME_TO_SEC("00:39:38");

mysql>
mysql>
mysql> SELECT TIME_TO_SEC("00:39:38");
+-------------------------+
| TIME_TO_SEC("00:39:38") |
+-------------------------+
|                    2378 |
+-------------------------+
1 row in set (0.00 sec)
mysql>

TIME_TO_SEC(time) returns the time argument, converted to seconds.

mysql>
mysql> SELECT TIME_TO_SEC("22:23:00");
+-------------------------+
| TIME_TO_SEC("22:23:00") |
+-------------------------+
|                   80580 |
+-------------------------+
1 row in set (0.00 sec)