private static int ymdToJulian(int year, int month, int day) {
    int a = (14 - month) / 12;
    int y = year + 4800 - a;
    int m = month + 12 * a - 3;
    return day + (153 * m + 2) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 32045;
  }
Converts the Java type used for UDF parameters of SQL TIMESTAMP type ({@link Timestamp}) to
internal representation (long).

<p>Converse of {@link #toSQLTimestamp(long)}.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java