MySQL:

TIME_TO_SEC

Syntax:
TIME_TO_SEC(time)

Returns the time argument, converted to seconds.

URL: https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html

mysql> SELECT TIME_TO_SEC('22:23:00');
-> 80580
mysql> SELECT TIME_TO_SEC('00:39:38');
-> 2378

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