presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/hourFromTime
class DateTimeFunctions:    @Description("hour of the day of the given time")
    @ScalarFunction("hour")
    @SqlType(StandardTypes.BIGINT)
    public static long hourFromTime(ConnectorSession session, @SqlType(StandardTypes.TIME) long time)
    {
        if (session.isLegacyTimestamp()) {
            return getChronology(session.getTimeZoneKey()).hourOfDay().get(time);
        }
        else {
            return HOUR_OF_DAY.get(time);
        }
    }