private static void fraction(StringBuilder buf, int scale, long ms) {
    if (scale > 0) {
      buf.append('.');
      long v1 = scale == 3 ? ms : scale == 2 ? ms / 10 : scale == 1 ? ms / 100 : 0;
      number(buf, (int) v1, scale);
    }
  }
Helper for CAST({date} AS VARCHAR(n)).
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java