presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/hourFromTimestampWithTimeZone
class DateTimeFunctions:    @Description("hour of the day of the given timestamp")
    @ScalarFunction("hour")
    @SqlType(StandardTypes.BIGINT)
    public static long hourFromTimestampWithTimeZone(@SqlType(StandardTypes.TIMESTAMP_WITH_TIME_ZONE) long timestampWithTimeZone)
    {
        return unpackChronology(timestampWithTimeZone).hourOfDay().get(unpackMillisUtc(timestampWithTimeZone));
    }