private static long zeroLastDigits(long l, int n) {
    long tenToTheN = (long) Math.pow(10, n);
    return (l / tenToTheN) * tenToTheN;
  }
Appends year-month-day to a buffer; assumes they are valid.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java