Syntax:
HOUR(time)

Returns the hour for time. The range of the return value is 0 to 23 for
time-of-day values. However, the range of TIME values actually is much
larger, so HOUR can return values greater than 23. Returns NULL if time
is NULL.

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

