@Deprecated
  public java.sql.Timestamp add(java.sql.Timestamp ts, HiveIntervalDayTime interval) {
    if (ts == null || interval == null) {
      return null;
    }

    java.sql.Timestamp tsResult = new java.sql.Timestamp(0);
    add(ts, interval, tsResult);

    return tsResult;
  }
Perform date + int operation .
@param dt the date
@param interval the int (days)
@return the resulting date
ql/src/java/org/apache/hadoop/hive/ql/util/DateTimeMath.java